C# language server crashes

[Qythyx]

Type: Bug

I can't reproduce this on demand, but it happens usually a few times per day.

Extension version: 2.130.5
VS Code version: Code 1.115.0 (Universal) (41dd792b5e652393e7787322889ed5fdc58bd75b, 2026-04-07T22:04:57Z)
OS version: Darwin arm64 25.4.0
Modes:
Remote OS version: Darwin arm64 25.3.0

System Info

Item	Value
CPUs	Apple M4 Max (16 x 2400)
GPU Status	2d_canvas: enabled GPU0: VENDOR= 0x106b [Google Inc. (Apple)], DEVICE=0x0000 [ANGLE (Apple, ANGLE Metal Renderer: Apple M4 Max, Version 26.4.1 (Build 25E253))], DRIVER_VENDOR=Apple, DRIVER_VERSION=26.4.1 ACTIVE Machine model name: Mac Machine model version: 16.5 direct_rendering_display_compositor: disabled_off_ok gpu_compositing: enabled multiple_raster_threads: enabled_on opengl: enabled_on rasterization: enabled raw_draw: disabled_off_ok skia_graphite: enabled_on trees_in_viz: disabled_off video_decode: enabled video_encode: enabled webgl: enabled webgl2: enabled webgpu: enabled webnn: disabled_off
Load (avg)	3, 3, 2
Memory (System)	64.00GB (1.64GB free)
Process Argv	--crash-reporter-id 28041dfc-f800-49fe-8573-627851462eca
Screen Reader	no
VM	0%

Item	Value
Remote	SSH: Rainers-Mac-Studio.local
OS	Darwin arm64 25.3.0
CPUs	Apple M4 Max (16 x 2400)
Memory (System)	64.00GB (3.86GB free)
VM	0%

A/B Experiments

vsliv368:30146709
binariesv615:30325510
nativeloc1:31344060
dwcopilot:31170013
dwoutputs:31242946
copilot_t_ci:31333650
e5gg6876:31282496
pythonrdcb7:31342333
6518g693:31463988
aj953862:31281341
6abeh943:31336334
envsdeactivate2:31464701
cloudbuttont:31379625
3efgi100_wstrepl:31403338
bj468946:31457056
use-responses-api:31390855
je187915:31454425
ec5jj548:31422691
cp_cls_t_966_ss:31454198
8hhj4413:31478653
ge8j1254_inline_auto_hint_haiku:31491242
38bie571_auto:31426784
cp_cls_t_1081:31454832
conptydll_true:31489736
e9c30283:31461165
test_treatment2:31471001
idci7584:31464702
3bj34942:31489864
534a6447:31478749
chat:31457767
t-some:31486549
cpptoolson-v2:31475363
inline_hover_fd9bg283:31492073
23c7c724:31491644
ddid_t:31478206
getcmakediagnosticson:31489824
cp_cls_c_1082:31491634
f5b8g904_t:31489328
logging_enabled_new:31493367

[dibarbet]

@Qythyx if you are able to you, there are two things that would help

1. Share the logs as described by https://github.com/dotnet/vscode-csharp/blob/main/SUPPORT.md#capturing-activity-trace-logging
2. If the logs don't have any additional information, collecting a dump on crash would be super helpful, see https://github.com/dotnet/vscode-csharp/blob/main/SUPPORT.md#language-server-crashing

[Qythyx]

@dibarbet I had another crash and tried to follow the instructions you mentioned, but that page seems to be a bit out of date. I don't see any CSharp: Collect C# Logs command, but there is CSharp: Capture Log Output, although it seems that begins capturing when I run it, so it's too late after a crash happened. Since I can't reproduce the problem on demand I'm not sure capturing those logs or a trace is viable.

I did check the output panel for C# and found this:

2026-04-16 12:36:05.521 [error] Unhandled exception. System.ObjectDisposedException: Cannot access a disposed object.
2026-04-16 12:36:05.521 [error] Object name: 'System.Net.Security.SslStream'.
2026-04-16 12:36:05.521 [error]    at System.Net.Security.SslStream.<ThrowIfExceptional>g__ThrowExceptional|131_0(ExceptionDispatchInfo e)
2026-04-16 12:36:05.521 [error]    at System.Net.Security.SslStream.WriteAsyncInternal[TIOAdapter](ReadOnlyMemory`1 buffer, CancellationToken cancellationToken)
2026-04-16 12:36:05.521 [error]    at System.Net.Security.SslStream.Write(Byte[] buffer, Int32 offset, Int32 count)
2026-04-16 12:36:05.521 [error]    at Microsoft.VisualStudio.DesignTools.RuntimeHost.Networking.TcpNetworkStream.Write(Byte[] buffer)
2026-04-16 12:36:05.521 [error]    at Microsoft.VisualStudio.DesignTools.RuntimeHost.Networking.TcpDataBridge.WriteMessage(Byte[] buffer)
2026-04-16 12:36:05.521 [error]    at Microsoft.VisualStudio.DesignTools.RuntimeHost.Networking.ProtocolHandler.<>c__DisplayClass48_0.<PushMessageOnToSendQueue>b__0()
2026-04-16 12:36:05.521 [error]    at Microsoft.VisualStudio.DesignTools.RuntimeHost.Networking.ProtocolHandler.ActionThread(Object list)
2026-04-16 12:36:05.521 [error]    at System.Threading.Thread.StartHelper.Callback(Object state)
2026-04-16 12:36:05.521 [error]    at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state)
2026-04-16 12:36:05.521 [error] --- End of stack trace from previous location ---
2026-04-16 12:36:05.521 [error]    at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state)
2026-04-16 12:36:05.521 [error]    at System.Threading.Thread.StartCallback()
2026-04-16 12:36:05.529 [info] Connection to server got closed. Server will restart.
2026-04-16 12:36:05.531 [error] Server process exited with signal SIGABRT.
2026-04-16 12:36:05.594 [info] info: Program[0]
2026-04-16 12:36:05.594 [info]       Server started with process ID 33013
2026-04-16 12:36:05.855 [info] [Program] Language server initialized
2026-04-16 12:36:05.856 [info] [Program] Monitoring client process 16542 for exit
2026-04-16 12:36:06.461 [info] [textDocument/diagnostic] [Microsoft.CodeAnalysis.MSBuild.BuildHostProcessManager] .NET BuildHost started from /Users/rainer/.vscode-server/extensions/ms-dotnettools.csharp-2.130.5-darwin-arm64/.roslyn/Microsoft.CodeAnalysis.LanguageServer reloading to start from /usr/local/share/dotnet/dotnet to match necessary SDK location.
2026-04-16 12:36:06.926 [warning] [textDocument/diagnostic] [LanguageServerProjectLoader] Project /var/folders/vh/1f090pd90dj1qhknqb695d3w0000gn/T/roslyn-canonical-misc/ca1d07fa-50a7-48ef-9836-4d0d9e42c04c/Canonical.csproj has unresolved dependencies
2026-04-16 12:36:06.992 [info] [textDocument/diagnostic] [LanguageServerProjectLoader] Successfully completed load of /var/folders/vh/1f090pd90dj1qhknqb695d3w0000gn/T/roslyn-canonical-misc/ca1d07fa-50a7-48ef-9836-4d0d9e42c04c/Canonical.cs
2026-04-16 12:36:06.993 [info] [textDocument/diagnostic] [LanguageServerProjectLoader] Restoring Canonical.cs: Running dotnet restore on /var/folders/vh/1f090pd90dj1qhknqb695d3w0000gn/T/roslyn-canonical-misc/ca1d07fa-50a7-48ef-9836-4d0d9e42c04c/Canonical.cs
2026-04-16 12:36:06.993 [info] [textDocument/diagnostic] [Microsoft.CodeAnalysis.LanguageServer.DotnetCliHelper] Using dotnet executable configured on the PATH
2026-04-16 12:36:07.340 [info] [textDocument/diagnostic] [LanguageServerProjectLoader] Restoring Canonical.cs:   Determining projects to restore...
2026-04-16 12:36:08.071 [info] [textDocument/diagnostic] [LanguageServerProjectLoader] Restoring Canonical.cs:   Restored /var/folders/vh/1f090pd90dj1qhknqb695d3w0000gn/T/roslyn-canonical-misc/ca1d07fa-50a7-48ef-9836-4d0d9e42c04c/Canonical.csproj (in 628 ms).
2026-04-16 12:36:08.085 [info] [textDocument/diagnostic] [LanguageServerProjectLoader] Restore complete
2026-04-16 12:36:08.085 [info] [textDocument/diagnostic] [LanguageServerProjectLoader] Completed (re)load of all projects in 00:00:01.7946833

[dibarbet]

but that page seems to be a bit out of date. I don't see any CSharp: Collect C# Logs command

Ah, sorry - we updated all those commands in prerelease, it just hasn't quite made it to release yet. But the logs you got are helpful, appears to be the same issue as #9164 (another instance fyi @noiseonwires )