C# language server repeatedly exits with SIGKILL on macOS

Type: Bug

## Issue Description ##
## Steps to Reproduce ##

## Expected Behavior ##

## Actual Behavior ##

Extension version: 2.140.9
VS Code version: Code 1.134.0 (Universal) (110a328ea54b42367b803ec53ee0bf52ef26b419, 2026-08-18T18:24:44Z)
OS version: Darwin arm64 25.6.0
Modes:

### Logs ###

### C# log ###

```
2026-08-26 23:40:18.043 [info] Locating .NET runtime version 10.0.5
2026-08-26 23:40:18.269 [info] Dotnet path: /Users/cuneytergen/Library/Application Support/Code/User/globalStorage/ms-dotnettools.vscode-dotnet-runtime/.dotnet/10.0.11~arm64~aspnetcore/dotnet
2026-08-26 23:40:18.269 [info] Activating C# + C# Dev Kit...
2026-08-26 23:40:19.027 [info] info: Program[0]
2026-08-26 23:40:19.027 [info] Server started with process ID 82098
2026-08-26 23:40:20.059 [info] [Program] Language server initialized
2026-08-26 23:40:20.072 [info] [Program] Monitoring client process 81967 for exit
2026-08-26 23:40:20.564 [info] [initialized] [Microsoft.CodeAnalysis.LanguageServer.FileBasedPrograms.FileBasedProgramsEntryPointDiscovery] Finished discovery in '/Users/cuneytergen/Documents/Musteri Projeleri/old_Hayat/hayat-it-masterdata-backend' in 4 milliseconds
2026-08-26 23:40:20.581 [info] [initialized] [Microsoft.CodeAnalysis.LanguageServer.FileBasedPrograms.FileBasedProgramsEntryPointDiscovery] Finished discovery in '/Users/cuneytergen/Documents/Musteri Projeleri/old_Hayat/hayat-it-masterdata-ui' in 2 milliseconds
2026-08-26 23:40:23.732 [info] [serviceBroker/connect] [WorkspaceProjectFactoryService] Project /Users/cuneytergen/Documents/Musteri Projeleri/old_Hayat/hayat-it-masterdata-backend/src/MasterData.Domain/MasterData.Domain.csproj loaded by C# Dev Kit
2026-08-26 23:40:23.750 [info] [serviceBroker/connect] [WorkspaceProjectFactoryService] Project /Users/cuneytergen/Documents/Musteri Projeleri/old_Hayat/hayat-it-masterdata-backend/src/MasterData.Api/MasterData.Api.csproj loaded by C# Dev Kit
2026-08-26 23:40:23.754 [info] [serviceBroker/connect] [WorkspaceProjectFactoryService] Project /Users/cuneytergen/Documents/Musteri Projeleri/old_Hayat/hayat-it-masterdata-backend/src/MasterData.Infrastructure/MasterData.Infrastructure.csproj loaded by C# Dev Kit
2026-08-26 23:40:23.757 [info] [serviceBroker/connect] [WorkspaceProjectFactoryService] Project /Users/cuneytergen/Documents/Musteri Projeleri/old_Hayat/hayat-it-masterdata-backend/src/MasterData.Application/MasterData.Application.csproj loaded by C# Dev Kit
2026-08-26 23:42:04.646 [info] Connection to server got closed. Server will restart.
2026-08-26 23:42:04.649 [error] Server process exited with signal SIGKILL.
2026-08-26 23:42:04.772 [info] info: Program[0]
2026-08-26 23:42:04.772 [info] Server started with process ID 82388
2026-08-26 23:42:05.083 [info] [Program] Language server initialized
2026-08-26 23:42:05.084 [info] [Program] Monitoring client process 81967 for exit
2026-08-26 23:42:05.299 [info] [initialized] [Microsoft.CodeAnalysis.LanguageServer.FileBasedPrograms.FileBasedProgramsEntryPointDiscovery] Finished discovery in '/Users/cuneytergen/Documents/Musteri Projeleri/old_Hayat/hayat-it-masterdata-backend' in 3 milliseconds
2026-08-26 23:42:05.313 [info] [initialized] [Microsoft.CodeAnalysis.LanguageServer.FileBasedPrograms.FileBasedProgramsEntryPointDiscovery] Finished discovery in '/Users/cuneytergen/Documents/Musteri Projeleri/old_Hayat/hayat-it-masterdata-ui' in 3 milliseconds
2026-08-26 23:43:13.772 [info] Connection to server got closed. Server will restart.
2026-08-26 23:43:13.774 [error] Server process exited with signal SIGKILL.
2026-08-26 23:43:13.878 [info] info: Program[0]
2026-08-26 23:43:13.878 [info] Server started with process ID 82496
2026-08-26 23:43:14.171 [info] [Program] Language server initialized
2026-08-26 23:43:14.173 [info] [Program] Monitoring client process 81967 for exit
2026-08-26 23:43:14.380 [info] [initialized] [Microsoft.CodeAnalysis.LanguageServer.FileBasedPrograms.FileBasedProgramsEntryPointDiscovery] Finished discovery in '/Users/cuneytergen/Documents/Musteri Projeleri/old_Hayat/hayat-it-masterdata-backend' in 3 milliseconds
2026-08-26 23:43:14.395 [info] [initialized] [Microsoft.CodeAnalysis.LanguageServer.FileBasedPrograms.FileBasedProgramsEntryPointDiscovery] Finished discovery in '/Users/cuneytergen/Documents/Musteri Projeleri/old_Hayat/hayat-it-masterdata-ui' in 2 milliseconds
2026-08-26 23:43:50.880 [info] Connection to server got closed. Server will restart.
2026-08-26 23:43:50.882 [error] Server process exited with signal SIGKILL.
2026-08-26 23:43:50.983 [info] info: Program[0]
2026-08-26 23:43:50.983 [info] Server started with process ID 82590
2026-08-26 23:43:51.294 [info] [Program] Language server initialized
2026-08-26 23:43:51.295 [info] [Program] Monitoring client process 81967 for exit
2026-08-26 23:43:51.514 [info] [initialized] [Microsoft.CodeAnalysis.LanguageServer.FileBasedPrograms.FileBasedProgramsEntryPointDiscovery] Finished discovery in '/Users/cuneytergen/Documents/Musteri Projeleri/old_Hayat/hayat-it-masterdata-backend' in 3 milliseconds
2026-08-26 23:43:51.530 [info] [initialized] [Microsoft.CodeAnalysis.LanguageServer.FileBasedPrograms.FileBasedProgramsEntryPointDiscovery] Finished discovery in '/Users/cuneytergen/Documents/Musteri Projeleri/old_Hayat/hayat-it-masterdata-ui' in 2 milliseconds
2026-08-26 23:44:28.354 [info] Connection to server got closed. Server will restart.
2026-08-26 23:44:28.356 [error] Server process exited with signal SIGKILL.
2026-08-26 23:44:28.457 [info] info: Program[0]
2026-08-26 23:44:28.457 [info] Server started with process ID 82635
2026-08-26 23:44:28.779 [info] [Program] Language server initialized
2026-08-26 23:44:28.780 [info] [Program] Monitoring client process 81967 for exit
2026-08-26 23:44:28.991 [info] [initialized] [Microsoft.CodeAnalysis.LanguageServer.FileBasedPrograms.FileBasedProgramsEntryPointDiscovery] Finished discovery in '/Users/cuneytergen/Documents/Musteri Projeleri/old_Hayat/hayat-it-masterdata-backend' in 3 milliseconds
2026-08-26 23:44:29.009 [info] [initialized] [Microsoft.CodeAnalysis.LanguageServer.FileBasedPrograms.FileBasedProgramsEntryPointDiscovery] Finished discovery in '/Users/cuneytergen/Documents/Musteri Projeleri/old_Hayat/hayat-it-masterdata-ui' in 2 milliseconds

```

### C# LSP Trace Logs log ###

```

```

## Environment Information ##
**VSCode version**: 1.134.0
**C# Extension**: 2.140.9
**Using OmniSharp**: false

Dotnet Information

Host:
Version: 10.0.11
Architecture: arm64
Commit: e2f47b0110
RID: osx-arm64

.NET SDKs installed:
No SDKs were found.

.NET runtimes installed:
Microsoft.AspNetCore.App 10.0.11 [/Users/cuneytergen/Library/Application Support/Code/User/globalStorage/ms-dotnettools.vscode-dotnet-runtime/.dotnet/10.0.11~arm64~aspnetcore/shared/Microsoft.AspNetCore.App]
Microsoft.NETCore.App 10.0.11 [/Users/cuneytergen/Library/Application Support/Code/User/globalStorage/ms-dotnettools.vscode-dotnet-runtime/.dotnet/10.0.11~arm64~aspnetcore/shared/Microsoft.NETCore.App]

Other architectures found:
None

Environment variables:
DOTNET_CLI_UI_LANGUAGE [en-US]
DOTNET_NOLOGO [true]
DOTNET_ROOT [/Users/cuneytergen/.dotnet]

global.json file:
Not found

Learn more:
https://aka.ms/dotnet/info

Download .NET:
https://aka.ms/dotnet/download

Visual Studio Code Extensions

|Extension|Author|Version|Folder Name|
|---|---|---|---|
|claude-code|Anthropic|2.1.246|anthropic.claude-code-2.1.246-darwin-arm64|
|codespaces|GitHub|1.18.16|github.codespaces-1.18.16|
|csdevkit|ms-dotnettools|3.20.199|ms-dotnettools.csdevkit-3.20.199-darwin-arm64|
|csharp|ms-dotnettools|2.140.9|ms-dotnettools.csharp-2.140.9-darwin-arm64|
|powershell|ms-vscode|2025.4.0|ms-vscode.powershell-2025.4.0|
|volar|Vue|3.3.11|vue.volar-3.3.11|
|vscode-containers|ms-azuretools|2.5.0|ms-azuretools.vscode-containers-2.5.0|
|vscode-dotnet-runtime|ms-dotnettools|3.1.0|ms-dotnettools.vscode-dotnet-runtime-3.1.0|;

C# Settings

|Setting|Value|
|---|---|
|preferCSharpExtension|false|
|compilerDiagnosticScope|openFiles|
|analyzerDiagnosticScope|openFiles|
|enableXamlTools|true|
|useServerGC|true|;

System Info

|Item|Value|
|---|---|
|CPUs|Apple M1 (8 x 2400)|
|GPU Status|2d_canvas: enabled
GPU0: VENDOR= 0x106b [Google Inc. (Apple)], DEVICE=0x0000 [ANGLE (Apple, ANGLE Metal Renderer: Apple M1, Version 26.6.2 (Build 25G82))], DRIVER_VENDOR=Apple, DRIVER_VERSION=26.6.2 *ACTIVE*
Machine model name: MacBookPro
Machine model version: 17.1
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
webgpu: enabled
webnn: disabled_off|
|Load (avg)|2, 3, 3|
|Memory (System)|16.00GB (0.63GB free)|
|Process Argv|--crash-reporter-id 524dcf6b-10fe-4bf2-8cbf-bd569c3b2b8e|
|Screen Reader|no|
|VM|0%|

A/B Experiments

```
vsliv368cf:30146710
binariesv615:30325510
nativeloc1:31344060
dwcopilot:31170013
dwoutputs:31242946
copilot_t_ci:31333650
e5gg6876:31282496
pythonrdcb7:31342333
6518g693:31463988
aj953862:31281341
envsactivate1:31551504
cloudbuttont:31379625
3efgi100_wstrepl:31403338
ec5jj548:31422691
cp_cls_t_966_ss:31526232
4je02754:31572277
8hhj4413:31478653
cp_cls_c_1081:31454833
conptydll_true:31498968
e9c30283:31461165
test_treatment2:31471001
c9b86496:31447327
control_6dc23131:31555649
ei9d7968:31496641
chat:31457767
8hig5102:31480529
89g7j272:31518289
i2gc6536:31499202
52612955:31516516
ddid_t:31478206
hmra_i5g22:31518061
7df3h592:31512476
cp_cls_t_1082:31535311
logging_enabled_new:31498466
j0d79568:31499440
jb_cp_cls_t_632:31543129
56dj4588:31512888
32d76977:31512328
ha629193:31508444
a1ije391_t:31540920
jbcp_cls_pctr_t:31531130
61138546:31518536
cp_intellij_t_nes:31548657
gf14b233:31526830
ahp-both-windows:31556933
sessions_3:31532893
ihg5j128:31534457
f412h606:31551416
7g2b5551:31542111
sandbox-ui-on-2:31543161
nes-ex-cf-euporie-03:31542868
enable_editor_pane_layout:31569726
allow-none:31555437
36h42362:31564511
c7c27ce7:31554789
1h923230:31564177
0dg73464:31554319
treatment-23-1:31555779
unuse_dynamic_mcp:31555281
0d8dfbc3:31570291
0c1h4866:31566224
session-mark-done:31558131
5b8j3302:31564601
mangle-name-control:31572633
permission_prompt_treatment:1332566
ccr_pr_nudge_auto_review:1319472
vsc_wsm_c:1340633
eh853263:1355268

```

Start with the supplied C# log and reproduce on macOS arm64 using the listed VS Code, extension, and .NET versions. Enable C# LSP trace logging as described in SUPPORT.md and collect the full extension logs; done means the trigger for the repeated SIGKILL and restart cycle is isolated and a verified fix or actionable diagnosis is documented.

Written by the indexing model from the issue text.