Replace err_derive with thiserror

`err_derive` is unmaintained and will probably stop working with rust
edition 2024. `thiserror` is almost a drop-in replacement. This commit
simply replaces all occurences of `derive(err_derive::Error)` with
`derive(thiserror::Error)` and fixes the attributes, but the Error and
Display impls should be identical.

28 files changed, 268 insertions, 288 deletions

diff --git a/talpid-core/src/dns/android.rs b/talpid-core/src/dns/android.rs
index 3e9e0ef81b..6f4e110d3f 100644
--- a/talpid-core/src/dns/android.rs
+++ b/talpid-core/src/dns/android.rs
@@ -1,8 +1,8 @@
 use std::net::IpAddr;
 
 /// Stub error type for DNS errors on Android.
-#[derive(Debug, err_derive::Error)]
-#[error(display = "Unknown Android DNS error")]
+#[derive(Debug, thiserror::Error)]
+#[error("Unknown Android DNS error")]
 pub struct Error;
 
 pub struct DnsMonitor;
diff --git a/talpid-core/src/dns/linux/mod.rs b/talpid-core/src/dns/linux/mod.rs
index 38d15b4f5d..3e7f6ac0b8 100644
--- a/talpid-core/src/dns/linux/mod.rs
+++ b/talpid-core/src/dns/linux/mod.rs
@@ -13,26 +13,26 @@ use talpid_routing::RouteManagerHandle;
 pub type Result<T> = std::result::Result<T, Error>;
 
 /// Errors that can happen in the Linux DNS monitor
-#[derive(err_derive::Error, Debug)]
+#[derive(thiserror::Error, Debug)]
 pub enum Error {
     /// Error in systemd-resolved DNS monitor
-    #[error(display = "Error in systemd-resolved DNS monitor")]
-    SystemdResolved(#[error(source)] systemd_resolved::Error),
+    #[error("Error in systemd-resolved DNS monitor")]
+    SystemdResolved(#[from] systemd_resolved::Error),
 
     /// Error in NetworkManager DNS monitor
-    #[error(display = "Error in NetworkManager DNS monitor")]
-    NetworkManager(#[error(source)] network_manager::Error),
+    #[error("Error in NetworkManager DNS monitor")]
+    NetworkManager(#[from] network_manager::Error),
 
     /// Error in resolvconf DNS monitor
-    #[error(display = "Error in resolvconf DNS monitor")]
-    Resolvconf(#[error(source)] resolvconf::Error),
+    #[error("Error in resolvconf DNS monitor")]
+    Resolvconf(#[from] resolvconf::Error),
 
     /// Error in static /etc/resolv.conf DNS monitor
-    #[error(display = "Error in static /etc/resolv.conf DNS monitor")]
-    StaticResolvConf(#[error(source)] static_resolv_conf::Error),
+    #[error("Error in static /etc/resolv.conf DNS monitor")]
+    StaticResolvConf(#[from] static_resolv_conf::Error),
 
     /// No suitable DNS monitor implementation detected
-    #[error(display = "No suitable DNS monitor implementation detected")]
+    #[error("No suitable DNS monitor implementation detected")]
     NoDnsMonitor,
 }
 
diff --git a/talpid-core/src/dns/linux/resolvconf.rs b/talpid-core/src/dns/linux/resolvconf.rs
index 4c7c066f20..0e1ac33c30 100644
--- a/talpid-core/src/dns/linux/resolvconf.rs
+++ b/talpid-core/src/dns/linux/resolvconf.rs
@@ -10,27 +10,27 @@ use which::which;
 
 pub type Result<T> = std::result::Result<T, Error>;
 
-#[derive(err_derive::Error, Debug)]
+#[derive(thiserror::Error, Debug)]
 pub enum Error {
-    #[error(display = "Failed to detect 'resolvconf' program")]
+    #[error("Failed to detect 'resolvconf' program")]
     NoResolvconf,
 
-    #[error(display = "The resolvconf in PATH is just a symlink to systemd-resolved")]
+    #[error("The resolvconf in PATH is just a symlink to systemd-resolved")]
     ResolvconfUsesResolved,
 
-    #[error(display = "Failed to execute 'resolvconf' program")]
-    RunResolvconf(#[error(source)] io::Error),
+    #[error("Failed to execute 'resolvconf' program")]
+    RunResolvconf(#[from] io::Error),
 
-    #[error(display = "Using 'resolvconf' to add a record failed: {}", stderr)]
+    #[error("Using 'resolvconf' to add a record failed: {}", stderr)]
     AddRecord { stderr: String },
 
-    #[error(display = "Using 'resolvconf' to delete a record failed")]
+    #[error("Using 'resolvconf' to delete a record failed")]
     DeleteRecord,
 
-    #[error(display = "Detected dnsmasq is running and misconfigured")]
+    #[error("Detected dnsmasq is running and misconfigured")]
     DnsmasqMisconfiguration,
 
-    #[error(display = "Current /etc/resolv.conf is not generated by resolvconf")]
+    #[error("Current /etc/resolv.conf is not generated by resolvconf")]
     ResolvconfNotInUse,
 }
 
diff --git a/talpid-core/src/dns/linux/static_resolv_conf.rs b/talpid-core/src/dns/linux/static_resolv_conf.rs
index b1f28f5f52..59c5e2fbb9 100644
--- a/talpid-core/src/dns/linux/static_resolv_conf.rs
+++ b/talpid-core/src/dns/linux/static_resolv_conf.rs
@@ -11,22 +11,22 @@ const RESOLV_CONF_PATH: &str = "/etc/resolv.conf";
 
 pub type Result<T> = std::result::Result<T, Error>;
 
-#[derive(err_derive::Error, Debug)]
+#[derive(thiserror::Error, Debug)]
 pub enum Error {
-    #[error(display = "Failed to watch /etc/resolv.conf for changes")]
-    WatchResolvConf(#[error(source)] std::io::Error),
+    #[error("Failed to watch /etc/resolv.conf for changes")]
+    WatchResolvConf(#[source] std::io::Error),
 
-    #[error(display = "Failed to write to {}", _0)]
-    WriteResolvConf(&'static str, #[error(source)] io::Error),
+    #[error("Failed to write to {0}")]
+    WriteResolvConf(&'static str, #[source] io::Error),
 
-    #[error(display = "Failed to read from {}", _0)]
-    ReadResolvConf(&'static str, #[error(source)] io::Error),
+    #[error("Failed to read from {0}")]
+    ReadResolvConf(&'static str, #[source] io::Error),
 
-    #[error(display = "resolv.conf at {} could not be parsed", _0)]
-    Parse(&'static str, #[error(source)] resolv_conf::ParseError),
+    #[error("resolv.conf at {0} could not be parsed")]
+    Parse(&'static str, #[source] resolv_conf::ParseError),
 
-    #[error(display = "Failed to remove stale resolv.conf backup at {}", _0)]
-    RemoveBackup(&'static str, #[error(source)] io::Error),
+    #[error("Failed to remove stale resolv.conf backup at {0}")]
+    RemoveBackup(&'static str, #[source] io::Error),
 }
 
 pub struct StaticResolvConf {
diff --git a/talpid-core/src/dns/linux/systemd_resolved.rs b/talpid-core/src/dns/linux/systemd_resolved.rs
index 7094a5f28b..5e0e4a8409 100644
--- a/talpid-core/src/dns/linux/systemd_resolved.rs
+++ b/talpid-core/src/dns/linux/systemd_resolved.rs
@@ -8,13 +8,13 @@ pub(crate) use talpid_dbus::systemd_resolved::Error as SystemdDbusError;
 
 pub type Result<T> = std::result::Result<T, Error>;
 
-#[derive(err_derive::Error, Debug)]
+#[derive(thiserror::Error, Debug)]
 pub enum Error {
-    #[error(display = "systemd-resolved operation failed")]
-    SystemdResolvedError(#[error(source)] SystemdDbusError),
+    #[error("systemd-resolved operation failed")]
+    SystemdResolvedError(#[from] SystemdDbusError),
 
-    #[error(display = "Failed to resolve interface index with error {}", _0)]
-    InterfaceNameError(#[error(source)] IfaceIndexLookupError),
+    #[error("Failed to resolve interface index with error {0}")]
+    InterfaceNameError(#[from] IfaceIndexLookupError),
 }
 
 pub struct SystemdResolved {
diff --git a/talpid-core/src/dns/macos.rs b/talpid-core/src/dns/macos.rs
index 39bce1c094..c68165737f 100644
--- a/talpid-core/src/dns/macos.rs
+++ b/talpid-core/src/dns/macos.rs
@@ -28,30 +28,30 @@ use crate::tunnel_state_machine::TunnelCommand;
 pub type Result<T> = std::result::Result<T, Error>;
 
 /// Errors that can happen when setting/monitoring DNS on macOS.
-#[derive(err_derive::Error, Debug)]
+#[derive(thiserror::Error, Debug)]
 pub enum Error {
     /// Error while setting DNS servers
-    #[error(display = "Error while setting DNS servers")]
+    #[error("Error while setting DNS servers")]
     SettingDnsFailed,
 
     /// Failed to initialize dynamic store
-    #[error(display = "Failed to initialize dynamic store")]
+    #[error("Failed to initialize dynamic store")]
     DynamicStoreInitError,
 
     /// Failed to parse IP address from config string
-    #[error(display = "Failed to parse an IP address from a config string")]
+    #[error("Failed to parse an IP address from a config string")]
     AddrParseError(String, String, AddrParseError),
 
     /// Failed to obtain name for interface
-    #[error(display = "Failed to obtain interface name")]
+    #[error("Failed to obtain interface name")]
     GetInterfaceNameError,
 
     /// Failed to load interface config
-    #[error(display = "Failed to load interface config at path {}", _0)]
+    #[error("Failed to load interface config at path {0}")]
     LoadInterfaceConfigError(String),
 
     /// Failed to load DNS config
-    #[error(display = "Failed to load DNS config at path {}", _0)]
+    #[error("Failed to load DNS config at path {0}")]
     LoadDnsConfigError(String),
 }
 
diff --git a/talpid-core/src/dns/windows/dnsapi.rs b/talpid-core/src/dns/windows/dnsapi.rs
index b9458a70b9..cd7731119b 100644
--- a/talpid-core/src/dns/windows/dnsapi.rs
+++ b/talpid-core/src/dns/windows/dnsapi.rs
@@ -13,19 +13,18 @@ static DNSAPI_HANDLE: OnceLock<DnsApi> = OnceLock::new();
 const MAX_CONCURRENT_FLUSHES: usize = 5;
 
 /// Errors that can happen when configuring DNS on Windows.
-#[derive(err_derive::Error, Debug)]
-#[error(no_from)]
+#[derive(thiserror::Error, Debug)]
 pub enum Error {
     /// Failed to flush the DNS cache.
-    #[error(display = "Call to flush DNS cache failed")]
+    #[error("Call to flush DNS cache failed")]
     FlushCache,
 
     /// Too many flush attempts in progress.
-    #[error(display = "Too many flush attempts in progress")]
+    #[error("Too many flush attempts in progress")]
     TooManyFlushAttempts,
 
     /// Flushing the DNS cache timed out.
-    #[error(display = "Timeout while flushing DNS cache")]
+    #[error("Timeout while flushing DNS cache")]
     Timeout,
 }
 
diff --git a/talpid-core/src/dns/windows/iphlpapi.rs b/talpid-core/src/dns/windows/iphlpapi.rs
index e48b3b65f5..fa47a695c1 100644
--- a/talpid-core/src/dns/windows/iphlpapi.rs
+++ b/talpid-core/src/dns/windows/iphlpapi.rs
@@ -30,32 +30,31 @@ use windows_sys::{
 };
 
 /// Errors that can happen when configuring DNS on Windows.
-#[derive(err_derive::Error, Debug)]
-#[error(no_from)]
+#[derive(thiserror::Error, Debug)]
 pub enum Error {
     /// Failure to obtain an interface LUID given an alias.
-    #[error(display = "Failed to obtain LUID for the interface alias")]
-    ObtainInterfaceLuid(#[error(source)] io::Error),
+    #[error("Failed to obtain LUID for the interface alias")]
+    ObtainInterfaceLuid(#[source] io::Error),
 
     /// Failure to obtain an interface GUID.
-    #[error(display = "Failed to obtain GUID for the interface")]
-    ObtainInterfaceGuid(#[error(source)] io::Error),
+    #[error("Failed to obtain GUID for the interface")]
+    ObtainInterfaceGuid(#[source] io::Error),
 
     /// Failed to set DNS settings on interface.
-    #[error(display = "Failed to set DNS settings on interface")]
-    SetInterfaceDnsSettings(#[error(source)] io::Error),
+    #[error("Failed to set DNS settings on interface")]
+    SetInterfaceDnsSettings(#[source] io::Error),
 
     /// Failure to flush DNS cache.
-    #[error(display = "Failed to flush DNS resolver cache")]
-    FlushResolverCache(#[error(source)] super::dnsapi::Error),
+    #[error("Failed to flush DNS resolver cache")]
+    FlushResolverCache(#[source] super::dnsapi::Error),
 
     /// Failed to load iphlpapi.dll.
-    #[error(display = "Failed to load iphlpapi.dll")]
-    LoadDll(#[error(source)] io::Error),
+    #[error("Failed to load iphlpapi.dll")]
+    LoadDll(#[source] io::Error),
 
     /// Failed to obtain exported function.
-    #[error(display = "Failed to obtain DNS function")]
-    GetFunction(#[error(source)] io::Error),
+    #[error("Failed to obtain DNS function")]
+    GetFunction(#[source] io::Error),
 }
 
 type SetInterfaceDnsSettingsFn = unsafe extern "stdcall" fn(
diff --git a/talpid-core/src/dns/windows/mod.rs b/talpid-core/src/dns/windows/mod.rs
index 4ab9976417..889f8b4126 100644
--- a/talpid-core/src/dns/windows/mod.rs
+++ b/talpid-core/src/dns/windows/mod.rs
@@ -9,19 +9,19 @@ mod netsh;
 mod tcpip;
 
 /// Errors that can happen when configuring DNS on Windows.
-#[derive(err_derive::Error, Debug)]
+#[derive(thiserror::Error, Debug)]
 pub enum Error {
     /// Failed to set DNS config using the iphlpapi module.
-    #[error(display = "Error in iphlpapi module")]
-    Iphlpapi(#[error(source)] iphlpapi::Error),
+    #[error("Error in iphlpapi module")]
+    Iphlpapi(#[from] iphlpapi::Error),
 
     /// Failed to set DNS config using the netsh module.
-    #[error(display = "Error in netsh module")]
-    Netsh(#[error(source)] netsh::Error),
+    #[error("Error in netsh module")]
+    Netsh(#[from] netsh::Error),
 
     /// Failed to set DNS config using the tcpip module.
-    #[error(display = "Error in tcpip module")]
-    Tcpip(#[error(source)] tcpip::Error),
+    #[error("Error in tcpip module")]
+    Tcpip(#[from] tcpip::Error),
 }
 
 pub struct DnsMonitor {
diff --git a/talpid-core/src/dns/windows/netsh.rs b/talpid-core/src/dns/windows/netsh.rs
index 7de3fe7900..25a11b826a 100644
--- a/talpid-core/src/dns/windows/netsh.rs
+++ b/talpid-core/src/dns/windows/netsh.rs
@@ -21,39 +21,38 @@ use windows_sys::Win32::{
 const NETSH_TIMEOUT: Duration = Duration::from_secs(10);
 
 /// Errors that can happen when configuring DNS on Windows.
-#[derive(err_derive::Error, Debug)]
-#[error(no_from)]
+#[derive(thiserror::Error, Debug)]
 pub enum Error {
     /// Failure to obtain an interface LUID given an alias.
-    #[error(display = "Failed to obtain LUID for the interface alias")]
-    ObtainInterfaceLuid(#[error(source)] io::Error),
+    #[error("Failed to obtain LUID for the interface alias")]
+    ObtainInterfaceLuid(#[source] io::Error),
 
     /// Failure to obtain an interface index.
-    #[error(display = "Failed to obtain index of the interface")]
-    ObtainInterfaceIndex(#[error(source)] io::Error),
+    #[error("Failed to obtain index of the interface")]
+    ObtainInterfaceIndex(#[source] io::Error),
 
     /// Failure to spawn netsh subprocess.
-    #[error(display = "Failed to spawn 'netsh'")]
-    SpawnNetsh(#[error(source)] io::Error),
+    #[error("Failed to spawn 'netsh'")]
+    SpawnNetsh(#[source] io::Error),
 
     /// Failure to spawn netsh subprocess.
-    #[error(display = "Failed to obtain system directory")]
-    GetSystemDir(#[error(source)] io::Error),
+    #[error("Failed to obtain system directory")]
+    GetSystemDir(#[source] io::Error),
 
     /// Failure to write to stdin.
-    #[error(display = "Failed to write to stdin for 'netsh'")]
-    NetshInput(#[error(source)] io::Error),
+    #[error("Failed to write to stdin for 'netsh'")]
+    NetshInput(#[source] io::Error),
 
     /// Failure to wait for netsh result.
-    #[error(display = "Failed to wait for 'netsh'")]
-    WaitNetsh(#[error(source)] io::Error),
+    #[error("Failed to wait for 'netsh'")]
+    WaitNetsh(#[source] io::Error),
 
     /// netsh returned a non-zero status.
-    #[error(display = "'netsh' returned an error: {:?}", _0)]
+    #[error("'netsh' returned an error: {0:?}")]
     Netsh(Option<i32>),
 
     /// netsh did not return in a timely manner.
-    #[error(display = "'netsh' took too long to complete")]
+    #[error("'netsh' took too long to complete")]
     NetshTimeout,
 }
 
diff --git a/talpid-core/src/dns/windows/tcpip.rs b/talpid-core/src/dns/windows/tcpip.rs
index 244417e119..7581d3c470 100644
--- a/talpid-core/src/dns/windows/tcpip.rs
+++ b/talpid-core/src/dns/windows/tcpip.rs
@@ -10,24 +10,23 @@ use winreg::{
 };
 
 /// Errors that can happen when configuring DNS on Windows.
-#[derive(err_derive::Error, Debug)]
-#[error(no_from)]
+#[derive(thiserror::Error, Debug)]
 pub enum Error {
     /// Failure to obtain an interface LUID given an alias.
-    #[error(display = "Failed to obtain LUID for the interface alias")]
-    ObtainInterfaceLuid(#[error(source)] io::Error),
+    #[error("Failed to obtain LUID for the interface alias")]
+    ObtainInterfaceLuid(#[source] io::Error),
 
     /// Failure to obtain an interface GUID.
-    #[error(display = "Failed to obtain GUID for the interface")]
-    ObtainInterfaceGuid(#[error(source)] io::Error),
+    #[error("Failed to obtain GUID for the interface")]
+    ObtainInterfaceGuid(#[source] io::Error),
 
     /// Failure to flush DNS cache.
-    #[error(display = "Failed to flush DNS resolver cache")]
-    FlushResolverCache(#[error(source)] super::dnsapi::Error),
+    #[error("Failed to flush DNS resolver cache")]
+    FlushResolverCache(#[source] super::dnsapi::Error),
 
     /// Failed to update DNS servers for interface.
-    #[error(display = "Failed to update interface DNS servers")]
-    SetResolvers(#[error(source)] io::Error),
+    #[error("Failed to update interface DNS servers")]
+    SetResolvers(#[source] io::Error),
 }
 
 pub struct DnsMonitor {
diff --git a/talpid-core/src/firewall/android.rs b/talpid-core/src/firewall/android.rs
index fc854bc804..b9fa1eb442 100644
--- a/talpid-core/src/firewall/android.rs
+++ b/talpid-core/src/firewall/android.rs
@@ -1,8 +1,8 @@
 use super::{FirewallArguments, FirewallPolicy};
 
 /// Stub error type for Firewall errors on Android.
-#[derive(Debug, err_derive::Error)]
-#[error(display = "Unknown Android Firewall error")]
+#[derive(Debug, thiserror::Error)]
+#[error("Unknown Android Firewall error")]
 pub struct Error;
 
 /// The Android stub implementation for the firewall.
diff --git a/talpid-core/src/firewall/linux.rs b/talpid-core/src/firewall/linux.rs
index 717945c649..7c3cb26ec7 100644
--- a/talpid-core/src/firewall/linux.rs
+++ b/talpid-core/src/firewall/linux.rs
@@ -22,36 +22,32 @@ const PROC_SYS_NET_IPV4_CONF_SRC_VALID_MARK: &str = "/proc/sys/net/ipv4/conf/all
 pub type Result<T> = std::result::Result<T, Error>;
 
 /// Errors that can happen when interacting with Linux netfilter.
-#[derive(err_derive::Error, Debug)]
-#[error(no_from)]
+#[derive(thiserror::Error, Debug)]
 pub enum Error {
     /// Unable to open netlink socket to netfilter.
-    #[error(display = "Unable to open netlink socket to netfilter")]
-    NetlinkOpenError(#[error(source)] io::Error),
+    #[error("Unable to open netlink socket to netfilter")]
+    NetlinkOpenError(#[source] io::Error),
 
     /// Unable to send netlink command to netfilter.
-    #[error(display = "Unable to send netlink command to netfilter")]
-    NetlinkSendError(#[error(source)] io::Error),
+    #[error("Unable to send netlink command to netfilter")]
+    NetlinkSendError(#[source] io::Error),
 
     /// Error while reading from netlink socket.
-    #[error(display = "Error while reading from netlink socket")]
-    NetlinkRecvError(#[error(source)] io::Error),
+    #[error("Error while reading from netlink socket")]
+    NetlinkRecvError(#[source] io::Error),
 
     /// Error while processing an incoming netlink message.
-    #[error(display = "Error while processing an incoming netlink message")]
-    ProcessNetlinkError(#[error(source)] io::Error),
+    #[error("Error while processing an incoming netlink message")]
+    ProcessNetlinkError(#[source] io::Error),
 
     /// Failed to verify that our tables are set. Probably means that
     /// it's the host that does not support nftables properly.
-    #[error(display = "Failed to set firewall rules")]
+    #[error("Failed to set firewall rules")]
     NetfilterTableNotSetError,
 
     /// Unable to translate network interface name into index.
-    #[error(
-        display = "Unable to translate network interface name \"{}\" into index",
-        _0
-    )]
-    LookupIfaceIndexError(String, #[error(source)] crate::linux::IfaceIndexLookupError),
+    #[error("Unable to translate network interface name \"{0}\" into index")]
+    LookupIfaceIndexError(String, #[source] crate::linux::IfaceIndexLookupError),
 }
 
 /// TODO(linus): This crate is not supposed to be Mullvad-aware. So at some point this should be
diff --git a/talpid-core/src/firewall/windows.rs b/talpid-core/src/firewall/windows.rs
index c751a283a5..eda06ce5fd 100644
--- a/talpid-core/src/firewall/windows.rs
+++ b/talpid-core/src/firewall/windows.rs
@@ -12,32 +12,31 @@ use widestring::WideCString;
 use windows_sys::Win32::Globalization::{MultiByteToWideChar, CP_ACP};
 
 /// Errors that can happen when configuring the Windows firewall.
-#[derive(err_derive::Error, Debug)]
-#[error(no_from)]
+#[derive(thiserror::Error, Debug)]
 pub enum Error {
     /// Failure to initialize windows firewall module
-    #[error(display = "Failed to initialize windows firewall module")]
+    #[error("Failed to initialize windows firewall module")]
     Initialization,
 
     /// Failure to deinitialize windows firewall module
-    #[error(display = "Failed to deinitialize windows firewall module")]
+    #[error("Failed to deinitialize windows firewall module")]
     Deinitialization,
 
     /// Failure to apply a firewall _connecting_ policy
-    #[error(display = "Failed to apply connecting firewall policy")]
-    ApplyingConnectingPolicy(#[error(source)] FirewallPolicyError),
+    #[error("Failed to apply connecting firewall policy")]
+    ApplyingConnectingPolicy(#[source] FirewallPolicyError),
 
     /// Failure to apply a firewall _connected_ policy
-    #[error(display = "Failed to apply connected firewall policy")]
-    ApplyingConnectedPolicy(#[error(source)] FirewallPolicyError),
+    #[error("Failed to apply connected firewall policy")]
+    ApplyingConnectedPolicy(#[source] FirewallPolicyError),
 
     /// Failure to apply firewall _blocked_ policy
-    #[error(display = "Failed to apply blocked firewall policy")]
-    ApplyingBlockedPolicy(#[error(source)] FirewallPolicyError),
+    #[error("Failed to apply blocked firewall policy")]
+    ApplyingBlockedPolicy(#[source] FirewallPolicyError),
 
     /// Failure to reset firewall policies
-    #[error(display = "Failed to reset firewall policies")]
-    ResettingPolicy(#[error(source)] FirewallPolicyError),
+    #[error("Failed to reset firewall policies")]
+    ResettingPolicy(#[source] FirewallPolicyError),
 }
 
 /// Timeout for acquiring the WFP transaction lock
diff --git a/talpid-core/src/linux/mod.rs b/talpid-core/src/linux/mod.rs
index 05655bf4be..4b5321e4f0 100644
--- a/talpid-core/src/linux/mod.rs
+++ b/talpid-core/src/linux/mod.rs
@@ -18,10 +18,10 @@ pub fn iface_index(name: &str) -> Result<libc::c_uint, IfaceIndexLookupError> {
     }
 }
 
-#[derive(Debug, err_derive::Error)]
+#[derive(Debug, thiserror::Error)]
 pub enum IfaceIndexLookupError {
-    #[error(display = "Invalid network interface name: {}", _0)]
-    InvalidInterfaceName(String, #[error(source)] ffi::NulError),
-    #[error(display = "Failed to get index for interface {}", _0)]
-    InterfaceLookupError(String, #[error(source)] io::Error),
+    #[error("Invalid network interface name: {0}")]
+    InvalidInterfaceName(String, #[source] ffi::NulError),
+    #[error("Failed to get index for interface {0}")]
+    InterfaceLookupError(String, #[source] io::Error),
 }
diff --git a/talpid-core/src/logging/mod.rs b/talpid-core/src/logging/mod.rs
index 3251a39799..0e15054dd4 100644
--- a/talpid-core/src/logging/mod.rs
+++ b/talpid-core/src/logging/mod.rs
@@ -1,9 +1,9 @@
 use std::{fs, io, path::Path};
 
 /// Unable to create new log file
-#[derive(err_derive::Error, Debug)]
-#[error(display = "Unable to create new log file")]
-pub struct RotateLogError(#[error(source)] io::Error);
+#[derive(thiserror::Error, Debug)]
+#[error("Unable to create new log file")]
+pub struct RotateLogError(#[from] io::Error);
 
 /// Create a new log file while backing up a previous version of it.
 ///
diff --git a/talpid-core/src/mpsc.rs b/talpid-core/src/mpsc.rs
index 6492796cfc..d95f99fc7b 100644
--- a/talpid-core/src/mpsc.rs
+++ b/talpid-core/src/mpsc.rs
@@ -1,8 +1,8 @@
 /// Error type for `Sender` trait.
-#[derive(err_derive::Error, Debug)]
+#[derive(thiserror::Error, Debug)]
 pub enum Error {
     /// The underlying channel is closed.
-    #[error(display = "Channel is closed")]
+    #[error("Channel is closed")]
     ChannelClosed,
 }
 
diff --git a/talpid-core/src/offline/android.rs b/talpid-core/src/offline/android.rs
index 936da896bd..7dc8389ed3 100644
--- a/talpid-core/src/offline/android.rs
+++ b/talpid-core/src/offline/android.rs
@@ -12,30 +12,21 @@ use jnix::{
 use std::sync::{Arc, Weak};
 use talpid_types::{android::AndroidContext, net::Connectivity, ErrorExt};
 
-#[derive(err_derive::Error, Debug)]
-#[error(no_from)]
+#[derive(thiserror::Error, Debug)]
 pub enum Error {
-    #[error(display = "Failed to attach Java VM to tunnel thread")]
-    AttachJvmToThread(#[error(source)] jni::errors::Error),
+    #[error("Failed to attach Java VM to tunnel thread")]
+    AttachJvmToThread(#[source] jni::errors::Error),
 
-    #[error(display = "Failed to call Java method {}.{}", _0, _1)]
-    CallMethod(
-        &'static str,
-        &'static str,
-        #[error(source)] jni::errors::Error,
-    ),
+    #[error("Failed to call Java method {0}.{1}")]
+    CallMethod(&'static str, &'static str, #[source] jni::errors::Error),
 
-    #[error(display = "Failed to create global reference to Java object")]
-    CreateGlobalRef(#[error(source)] jni::errors::Error),
+    #[error("Failed to create global reference to Java object")]
+    CreateGlobalRef(#[source] jni::errors::Error),
 
-    #[error(display = "Failed to find {}.{} method", _0, _1)]
-    FindMethod(
-        &'static str,
-        &'static str,
-        #[error(source)] jni::errors::Error,
-    ),
+    #[error("Failed to find {0}.{1} method")]
+    FindMethod(&'static str, &'static str, #[source] jni::errors::Error),
 
-    #[error(display = "Received an invalid result from {}.{}: {}", _0, _1, _2)]
+    #[error("Received an invalid result from {0}.{1}: {2}")]
     InvalidMethodResult(&'static str, &'static str, String),
 }
 
diff --git a/talpid-core/src/offline/linux.rs b/talpid-core/src/offline/linux.rs
index 6f37ef89e9..1bb07149bf 100644
--- a/talpid-core/src/offline/linux.rs
+++ b/talpid-core/src/offline/linux.rs
@@ -8,11 +8,10 @@ use talpid_types::{net::Connectivity, ErrorExt};
 
 pub type Result<T> = std::result::Result<T, Error>;
 
-#[derive(err_derive::Error, Debug)]
-#[error(no_from)]
+#[derive(thiserror::Error, Debug)]
 pub enum Error {
-    #[error(display = "The route manager returned an error")]
-    RouteManagerError(#[error(source)] talpid_routing::Error),
+    #[error("The route manager returned an error")]
+    RouteManagerError(#[source] talpid_routing::Error),
 }
 
 pub struct MonitorHandle {
diff --git a/talpid-core/src/offline/macos.rs b/talpid-core/src/offline/macos.rs
index dff62a975d..51596f77c2 100644
--- a/talpid-core/src/offline/macos.rs
+++ b/talpid-core/src/offline/macos.rs
@@ -22,10 +22,10 @@ use talpid_types::net::Connectivity;
 
 const SYNTHETIC_OFFLINE_DURATION: Duration = Duration::from_secs(1);
 
-#[derive(err_derive::Error, Debug)]
+#[derive(thiserror::Error, Debug)]
 pub enum Error {
-    #[error(display = "Failed to initialize route monitor")]
-    StartMonitorError(#[error(source)] talpid_routing::Error),
+    #[error("Failed to initialize route monitor")]
+    StartMonitorError(#[from] talpid_routing::Error),
 }
 
 pub struct MonitorHandle {
diff --git a/talpid-core/src/offline/windows.rs b/talpid-core/src/offline/windows.rs
index caa3ac8f5e..f47fe8dd4d 100644
--- a/talpid-core/src/offline/windows.rs
+++ b/talpid-core/src/offline/windows.rs
@@ -10,12 +10,12 @@ use talpid_routing::{get_best_default_route, CallbackHandle, EventType, RouteMan
 use talpid_types::{net::Connectivity, ErrorExt};
 use talpid_windows::net::AddressFamily;
 
-#[derive(err_derive::Error, Debug)]
+#[derive(thiserror::Error, Debug)]
 pub enum Error {
-    #[error(display = "Unable to create listener thread")]
-    ThreadCreationError(#[error(source)] io::Error),
-    #[error(display = "Failed to start connectivity monitor")]
-    ConnectivityMonitorError(#[error(source)] talpid_routing::Error),
+    #[error("Unable to create listener thread")]
+    ThreadCreationError(#[from] io::Error),
+    #[error("Failed to start connectivity monitor")]
+    ConnectivityMonitorError(#[from] talpid_routing::Error),
 }
 
 pub struct BroadcastListener {
diff --git a/talpid-core/src/resolver.rs b/talpid-core/src/resolver.rs
index ed703c86fd..4fffced977 100644
--- a/talpid-core/src/resolver.rs
+++ b/talpid-core/src/resolver.rs
@@ -54,16 +54,15 @@ pub(crate) async fn start_resolver() -> Result<ResolverHandle, Error> {
 }
 
 /// Resolver errors
-#[derive(err_derive::Error, Debug)]
-#[error(no_from)]
+#[derive(thiserror::Error, Debug)]
 pub enum Error {
     /// Failed to bind UDP socket
-    #[error(display = "Failed to bind UDP socket")]
-    UdpBindError(#[error(source)] io::Error),
+    #[error("Failed to bind UDP socket")]
+    UdpBindError(#[source] io::Error),
 
     /// Failed to get local address of a bound UDP socket
-    #[error(display = "Failed to get local address of a bound UDP socket")]
-    GetSocketAddrError(#[error(source)] io::Error),
+    #[error("Failed to get local address of a bound UDP socket")]
+    GetSocketAddrError(#[source] io::Error),
 }
 
 /// A filtering resolver. Listens on a specified port for DNS queries and responds queries for
diff --git a/talpid-core/src/split_tunnel/linux.rs b/talpid-core/src/split_tunnel/linux.rs
index 67d671d13c..787ced68da 100644
--- a/talpid-core/src/split_tunnel/linux.rs
+++ b/talpid-core/src/split_tunnel/linux.rs
@@ -16,36 +16,35 @@ pub const NET_CLS_CLASSID: u32 = 0x4d9f41;
 pub const MARK: i32 = 0xf41;
 
 /// Errors related to split tunneling.
-#[derive(err_derive::Error, Debug)]
-#[error(no_from)]
+#[derive(thiserror::Error, Debug)]
 pub enum Error {
     /// Unable to create cgroup.
-    #[error(display = "Unable to initialize net_cls cgroup instance")]
-    InitNetClsCGroup(#[error(source)] nix::Error),
+    #[error("Unable to initialize net_cls cgroup instance")]
+    InitNetClsCGroup(#[source] nix::Error),
 
     /// Unable to create cgroup.
-    #[error(display = "Unable to create cgroup for excluded processes")]
-    CreateCGroup(#[error(source)] io::Error),
+    #[error("Unable to create cgroup for excluded processes")]
+    CreateCGroup(#[source] io::Error),
 
     /// Unable to set class ID for cgroup.
-    #[error(display = "Unable to set cgroup class ID")]
-    SetCGroupClassId(#[error(source)] io::Error),
+    #[error("Unable to set cgroup class ID")]
+    SetCGroupClassId(#[source] io::Error),
 
     /// Unable to add PID to cgroup.procs.
-    #[error(display = "Unable to add PID to cgroup.procs")]
-    AddCGroupPid(#[error(source)] io::Error),
+    #[error("Unable to add PID to cgroup.procs")]
+    AddCGroupPid(#[source] io::Error),
 
     /// Unable to remove PID to cgroup.procs.
-    #[error(display = "Unable to remove PID from cgroup")]
-    RemoveCGroupPid(#[error(source)] io::Error),
+    #[error("Unable to remove PID from cgroup")]
+    RemoveCGroupPid(#[source] io::Error),
 
     /// Unable to read cgroup.procs.
-    #[error(display = "Unable to obtain PIDs from cgroup.procs")]
-    ListCGroupPids(#[error(source)] io::Error),
+    #[error("Unable to obtain PIDs from cgroup.procs")]
+    ListCGroupPids(#[source] io::Error),
 
     /// Unable to read /proc/mounts
-    #[error(display = "Failed to read /proc/mounts")]
-    ListMounts(#[error(source)] io::Error),
+    #[error("Failed to read /proc/mounts")]
+    ListMounts(#[source] io::Error),
 }
 
 /// Manages PIDs in the Linux Cgroup excluded from the VPN tunnel.
diff --git a/talpid-core/src/split_tunnel/windows/driver.rs b/talpid-core/src/split_tunnel/windows/driver.rs
index 3f5a4e6a6d..ab1edf86f9 100644
--- a/talpid-core/src/split_tunnel/windows/driver.rs
+++ b/talpid-core/src/split_tunnel/windows/driver.rs
@@ -81,8 +81,8 @@ pub enum DriverState {
     Terminating = 5,
 }
 
-#[derive(err_derive::Error, Debug)]
-#[error(display = "Unknown driver state: {}", _0)]
+#[derive(thiserror::Error, Debug)]
+#[error("Unknown driver state: {0}")]
 pub struct UnknownDriverState(u64);
 
 impl TryFrom<u64> for DriverState {
@@ -117,8 +117,8 @@ pub enum EventId {
     ErrorMessage,
 }
 
-#[derive(err_derive::Error, Debug)]
-#[error(display = "Unknown event id: {}", _0)]
+#[derive(thiserror::Error, Debug)]
+#[error("Unknown event id: {0}")]
 pub struct UnknownEventId(u32);
 
 impl TryFrom<u32> for EventId {
@@ -170,42 +170,45 @@ pub struct DeviceHandle {
 unsafe impl Sync for DeviceHandle {}
 unsafe impl Send for DeviceHandle {}
 
-#[derive(err_derive::Error, Debug)]
-#[error(no_from)]
+#[derive(thiserror::Error, Debug)]
 pub enum DeviceHandleError {
     /// Failed to connect because there's no such device
-    #[error(display = "Failed to connect to driver, no such device. \
-            The driver is probably not loaded")]
+    #[error(
+        "Failed to connect to driver, no such device. \
+            The driver is probably not loaded"
+    )]
     ConnectionFailed,
 
     /// Failed to connect because the connection was denied
-    #[error(display = "Failed to connect to driver, connection denied. \
-            The exclusive connection is probably hogged")]
+    #[error(
+        "Failed to connect to driver, connection denied. \
+            The exclusive connection is probably hogged"
+    )]
     ConnectionDenied,
 
     /// Failed to connect to driver
-    #[error(display = "Failed to connect to driver")]
-    ConnectionError(#[error(source)] io::Error),
+    #[error("Failed to connect to driver")]
+    ConnectionError(#[source] io::Error),
 
     /// Failed to inquire about driver state
-    #[error(display = "Failed to inquire about driver state")]
-    GetStateError(#[error(source)] io::Error),
+    #[error("Failed to inquire about driver state")]
+    GetStateError(#[source] io::Error),
 
     /// Failed to initialize driver
-    #[error(display = "Failed to initialize driver")]
-    InitializationError(#[error(source)] io::Error),
+    #[error("Failed to initialize driver")]
+    InitializationError(#[source] io::Error),
 
     /// Failed to register process tree with driver
-    #[error(display = "Failed to register process tree with driver")]
-    RegisterProcessesError(#[error(source)] io::Error),
+    #[error("Failed to register process tree with driver")]
+    RegisterProcessesError(#[source] io::Error),
 
     /// Failed to clear configuration in driver
-    #[error(display = "Failed to clear configuration in driver")]
-    ClearConfigError(#[error(source)] io::Error),
+    #[error("Failed to clear configuration in driver")]
+    ClearConfigError(#[source] io::Error),
 
     /// Failed to reset driver state to "started"
-    #[error(display = "Failed to reset driver state")]
-    ResetError(#[error(source)] io::Error),
+    #[error("Failed to reset driver state")]
+    ResetError(#[source] io::Error),
 }
 
 impl DeviceHandle {
diff --git a/talpid-core/src/split_tunnel/windows/mod.rs b/talpid-core/src/split_tunnel/windows/mod.rs
index c5b08706ff..68030691a9 100644
--- a/talpid-core/src/split_tunnel/windows/mod.rs
+++ b/talpid-core/src/split_tunnel/windows/mod.rs
@@ -31,75 +31,74 @@ const DRIVER_EVENT_BUFFER_SIZE: usize = 2048;
 const RESERVED_IP_V4: Ipv4Addr = Ipv4Addr::new(192, 0, 2, 123);
 
 /// Errors that may occur in [`SplitTunnel`].
-#[derive(err_derive::Error, Debug)]
-#[error(no_from)]
+#[derive(thiserror::Error, Debug)]
 pub enum Error {
     /// Failed to install or start driver service
-    #[error(display = "Failed to start driver service")]
-    ServiceError(#[error(source)] service::Error),
+    #[error("Failed to start driver service")]
+    ServiceError(#[source] service::Error),
 
     /// Failed to initialize the driver
-    #[error(display = "Failed to initialize driver")]
-    InitializationError(#[error(source)] driver::DeviceHandleError),
+    #[error("Failed to initialize driver")]
+    InitializationError(#[source] driver::DeviceHandleError),
 
     /// Failed to reset the driver
-    #[error(display = "Failed to reset driver")]
-    ResetError(#[error(source)] io::Error),
+    #[error("Failed to reset driver")]
+    ResetError(#[source] io::Error),
 
     /// Failed to set paths to excluded applications
-    #[error(display = "Failed to set list of excluded applications")]
-    SetConfiguration(#[error(source)] io::Error),
+    #[error("Failed to set list of excluded applications")]
+    SetConfiguration(#[source] io::Error),
 
     /// Failed to obtain the current driver state
-    #[error(display = "Failed to obtain the driver state")]
-    GetState(#[error(source)] io::Error),
+    #[error("Failed to obtain the driver state")]
+    GetState(#[source] io::Error),
 
     /// Failed to register interface IP addresses
-    #[error(display = "Failed to register IP addresses for exclusions")]
-    RegisterIps(#[error(source)] io::Error),
+    #[error("Failed to register IP addresses for exclusions")]
+    RegisterIps(#[source] io::Error),
 
     /// Failed to clear interface IP addresses
-    #[error(display = "Failed to clear registered IP addresses")]
-    ClearIps(#[error(source)] io::Error),
+    #[error("Failed to clear registered IP addresses")]
+    ClearIps(#[source] io::Error),
 
     /// Failed to set up the driver event loop
-    #[error(display = "Failed to set up the driver event loop")]
-    EventThreadError(#[error(source)] io::Error),
+    #[error("Failed to set up the driver event loop")]
+    EventThreadError(#[source] io::Error),
 
     /// Failed to obtain default route
-    #[error(display = "Failed to obtain the default route")]
-    ObtainDefaultRoute(#[error(source)] talpid_routing::Error),
+    #[error("Failed to obtain the default route")]
+    ObtainDefaultRoute(#[source] talpid_routing::Error),
 
     /// Failed to obtain an IP address given a network interface LUID
-    #[error(display = "Failed to obtain IP address for interface LUID")]
-    LuidToIp(#[error(source)] talpid_windows::net::Error),
+    #[error("Failed to obtain IP address for interface LUID")]
+    LuidToIp(#[source] talpid_windows::net::Error),
 
     /// Failed to set up callback for monitoring default route changes
-    #[error(display = "Failed to register default route change callback")]
+    #[error("Failed to register default route change callback")]
     RegisterRouteChangeCallback,
 
     /// Unexpected IP parsing error
-    #[error(display = "Failed to parse IP address")]
+    #[error("Failed to parse IP address")]
     IpParseError,
 
     /// The request handling thread is stuck
-    #[error(display = "The ST request thread is stuck")]
+    #[error("The ST request thread is stuck")]
     RequestThreadStuck,
 
     /// The request handling thread is down
-    #[error(display = "The split tunnel monitor is down")]
+    #[error("The split tunnel monitor is down")]
     SplitTunnelDown,
 
     /// Failed to start the NTFS reparse point monitor
-    #[error(display = "Failed to start path monitor")]
-    StartPathMonitor(#[error(source)] io::Error),
+    #[error("Failed to start path monitor")]
+    StartPathMonitor(#[source] io::Error),
 
     /// A previous path update has not yet completed
-    #[error(display = "A previous update is not yet complete")]
+    #[error("A previous update is not yet complete")]
     AlreadySettingPaths,
 
     /// Resetting in the engaged state risks leaking into the tunnel
-    #[error(display = "Failed to reset driver because it is engaged")]
+    #[error("Failed to reset driver because it is engaged")]
     CannotResetEngaged,
 }
 
diff --git a/talpid-core/src/split_tunnel/windows/service.rs b/talpid-core/src/split_tunnel/windows/service.rs
index e71e9abc1d..95756acca8 100644
--- a/talpid-core/src/split_tunnel/windows/service.rs
+++ b/talpid-core/src/split_tunnel/windows/service.rs
@@ -19,44 +19,43 @@ const DRIVER_FILENAME: &str = "mullvad-split-tunnel.sys";
 
 const WAIT_STATUS_TIMEOUT: Duration = Duration::from_secs(8);
 
-#[derive(err_derive::Error, Debug)]
-#[error(no_from)]
+#[derive(thiserror::Error, Debug)]
 pub enum Error {
     /// Failed to open service control manager
-    #[error(display = "Failed to connect to service control manager")]
-    OpenServiceControlManager(#[error(source)] windows_service::Error),
+    #[error("Failed to connect to service control manager")]
+    OpenServiceControlManager(#[source] windows_service::Error),
 
     /// Failed to create a service handle
-    #[error(display = "Failed to open service")]
-    OpenServiceHandle(#[error(source)] windows_service::Error),
+    #[error("Failed to open service")]
+    OpenServiceHandle(#[source] windows_service::Error),
 
     /// Failed to start split tunnel service
-    #[error(display = "Failed to start split tunnel device driver service")]
-    StartService(#[error(source)] windows_service::Error),
+    #[error("Failed to start split tunnel device driver service")]
+    StartService(#[source] windows_service::Error),
 
     /// Failed to check service status
-    #[error(display = "Failed to query service status")]
-    QueryServiceStatus(#[error(source)] windows_service::Error),
+    #[error("Failed to query service status")]
+    QueryServiceStatus(#[source] windows_service::Error),
 
     /// Failed to open service config
-    #[error(display = "Failed to retrieve service config")]
-    QueryServiceConfig(#[error(source)] windows_service::Error),
+    #[error("Failed to retrieve service config")]
+    QueryServiceConfig(#[source] windows_service::Error),
 
     /// Failed to install ST service
-    #[error(display = "Failed to install split tunnel driver")]
-    InstallService(#[error(source)] windows_service::Error),
+    #[error("Failed to install split tunnel driver")]
+    InstallService(#[source] windows_service::Error),
 
     /// Failed to start ST service
-    #[error(display = "Timed out waiting on service to start")]
+    #[error("Timed out waiting on service to start")]
     StartTimeout,
 
     /// Failed to connect to existing driver
-    #[error(display = "Failed to open service handle")]
-    OpenHandle(#[error(source)] super::driver::DeviceHandleError),
+    #[error("Failed to open service handle")]
+    OpenHandle(#[source] super::driver::DeviceHandleError),
 
     /// Failed to reset existing driver
-    #[error(display = "Failed to reset driver state")]
-    ResetDriver(#[error(source)] io::Error),
+    #[error("Failed to reset driver state")]
+    ResetDriver(#[source] io::Error),
 }
 
 pub fn install_driver_if_required(resource_dir: &Path) -> Result<(), Error> {
diff --git a/talpid-core/src/tunnel/mod.rs b/talpid-core/src/tunnel/mod.rs
index 3ef05201b5..0daa8b996c 100644
--- a/talpid-core/src/tunnel/mod.rs
+++ b/talpid-core/src/tunnel/mod.rs
@@ -24,35 +24,35 @@ const DEFAULT_MTU: u16 = if cfg!(target_os = "android") {
 pub type Result<T> = std::result::Result<T, Error>;
 
 /// Errors that can occur in the [`TunnelMonitor`].
-#[derive(err_derive::Error, Debug)]
+#[derive(thiserror::Error, Debug)]
 pub enum Error {
     /// Tunnel can't have IPv6 enabled because the system has disabled IPv6 support.
-    #[error(display = "Can't enable IPv6 on tunnel interface because IPv6 is disabled")]
+    #[error("Can't enable IPv6 on tunnel interface because IPv6 is disabled")]
     EnableIpv6Error,
 
     /// Running on an operating system which is not supported yet.
-    #[error(display = "Tunnel type not supported on this operating system")]
+    #[error("Tunnel type not supported on this operating system")]
     UnsupportedPlatform,
 
     /// Failed to rotate tunnel log file
-    #[error(display = "Failed to rotate tunnel log file")]
-    RotateLogError(#[error(source)] crate::logging::RotateLogError),
+    #[error("Failed to rotate tunnel log file")]
+    RotateLogError(#[from] crate::logging::RotateLogError),
 
     /// Failure to build Wireguard configuration.
-    #[error(display = "Failed to configure Wireguard with the given parameters")]
-    WireguardConfigError(#[error(source)] talpid_wireguard::config::Error),
+    #[error("Failed to configure Wireguard with the given parameters")]
+    WireguardConfigError(#[from] talpid_wireguard::config::Error),
 
     /// There was an error listening for events from the OpenVPN tunnel
     #[cfg(not(target_os = "android"))]
-    #[error(display = "Failed while listening for events from the OpenVPN tunnel")]
-    OpenVpnTunnelMonitoringError(#[error(source)] talpid_openvpn::Error),
+    #[error("Failed while listening for events from the OpenVPN tunnel")]
+    OpenVpnTunnelMonitoringError(#[from] talpid_openvpn::Error),
 
     /// There was an error listening for events from the Wireguard tunnel
-    #[error(display = "Failed while listening for events from the Wireguard tunnel")]
-    WireguardTunnelMonitoringError(#[error(source)] talpid_wireguard::Error),
+    #[error("Failed while listening for events from the Wireguard tunnel")]
+    WireguardTunnelMonitoringError(#[from] talpid_wireguard::Error),
 
     /// Could not detect and assign the correct mtu
-    #[error(display = "Could not detect and assign a correct MTU for the Wireguard tunnel")]
+    #[error("Could not detect and assign a correct MTU for the Wireguard tunnel")]
     AssignMtuError,
 }
 
diff --git a/talpid-core/src/tunnel_state_machine/mod.rs b/talpid-core/src/tunnel_state_machine/mod.rs
index 6be9b8a1c3..26a03328a4 100644
--- a/talpid-core/src/tunnel_state_machine/mod.rs
+++ b/talpid-core/src/tunnel_state_machine/mod.rs
@@ -49,40 +49,40 @@ use talpid_types::{
 const TUNNEL_STATE_MACHINE_SHUTDOWN_TIMEOUT: Duration = Duration::from_secs(5);
 
 /// Errors that can happen when setting up or using the state machine.
-#[derive(err_derive::Error, Debug)]
+#[derive(thiserror::Error, Debug)]
 pub enum Error {
     /// Unable to spawn offline state monitor
-    #[error(display = "Unable to spawn offline state monitor")]
-    OfflineMonitorError(#[error(source)] crate::offline::Error),
+    #[error("Unable to spawn offline state monitor")]
+    OfflineMonitorError(#[from] crate::offline::Error),
 
     /// Unable to set up split tunneling
     #[cfg(target_os = "windows")]
-    #[error(display = "Failed to initialize split tunneling")]
-    InitSplitTunneling(#[error(source)] split_tunnel::Error),
+    #[error("Failed to initialize split tunneling")]
+    InitSplitTunneling(#[from] split_tunnel::Error),
 
     /// Failed to initialize the system firewall integration.
-    #[error(display = "Failed to initialize the system firewall integration")]
-    InitFirewallError(#[error(source)] crate::firewall::Error),
+    #[error("Failed to initialize the system firewall integration")]
+    InitFirewallError(#[from] crate::firewall::Error),
 
     /// Failed to initialize the system DNS manager and monitor.
-    #[error(display = "Failed to initialize the system DNS manager and monitor")]
-    InitDnsMonitorError(#[error(source)] crate::dns::Error),
+    #[error("Failed to initialize the system DNS manager and monitor")]
+    InitDnsMonitorError(#[from] crate::dns::Error),
 
     /// Failed to initialize the route manager.
-    #[error(display = "Failed to initialize the route manager")]
-    InitRouteManagerError(#[error(source)] talpid_routing::Error),
+    #[error("Failed to initialize the route manager")]
+    InitRouteManagerError(#[from] talpid_routing::Error),
 
     /// Failed to initialize filtering resolver
     #[cfg(target_os = "macos")]
-    #[error(display = "Failed to initialize filtering resolver")]
-    InitFilteringResolver(#[error(source)] crate::resolver::Error),
+    #[error("Failed to initialize filtering resolver")]
+    InitFilteringResolver(#[from] crate::resolver::Error),
 
     /// Failed to initialize tunnel state machine event loop executor
-    #[error(display = "Failed to initialize tunnel state machine event loop executor")]
-    ReactorError(#[error(source)] io::Error),
+    #[error("Failed to initialize tunnel state machine event loop executor")]
+    ReactorError(#[from] io::Error),
 
     /// Failed to send state change event to listener
-    #[error(display = "Failed to send state change event to listener")]
+    #[error("Failed to send state change event to listener")]
     SendStateChange,
 }