Skip to content

C# Extension Crashes When Saving New File Created via ".NET New File" in VS Code #8675

Open
Open
C# Extension Crashes When Saving New File Created via ".NET New File" in VS Code#8675
Labels
untriaged
@florestankorp

Description

@florestankorp
florestankorp
opened on Oct 2, 2025

Type: Bug

Issue Description

Whenever I create a new file in Visual Studio Code using the ".NET New File" command and attempt to save it, the C# extension crashes. The output window shows repeated errors such as "Failed to get language for textDocument/diagnostic" and "Document pull failed for text document untitled:Untitled-1". This issue occurs consistently and prevents saving new files created through the ".NET New File" workflow.

Steps to Reproduce

  1. Create a new file in VS Code using the ".NET New File" command
  2. Try to save the file
  3. Observe that C# crashes with the error above

Expected Behavior

The file should be saved without crashing the C# extension.

Actual Behavior

C# crashes with the error message above when saving a new file created via ".NET New File".

Image

Extension version: 2.90.60
VS Code version: Code 1.104.2 (e3a5acfb517a443235981655413d566533107e92, 2025-09-24T11:21:37.073Z)
OS version: Darwin arm64 24.6.0
Modes:

Logs

C# log

Details 
2025-10-02 11:37:36.318 [info] Locating .NET runtime version 9.0.1
2025-10-02 11:37:36.377 [info] Dotnet path: /usr/local/share/dotnet/dotnet
2025-10-02 11:37:36.377 [info] Activating C# + C# Dev Kit...
2025-10-02 11:37:36.454 [info] [stdout] info: Program[0]
      Server started with process ID 3563

2025-10-02 11:37:36.708 [info] [stdout] {"pipeName":"/var/folders/lc/nf0p2stx0rld6r95vd22s28h0000gn/T/7403409d.sock"}

2025-10-02 11:37:36.708 [info] received named pipe information from server
2025-10-02 11:37:36.709 [info] client has connected to server
2025-10-02 11:37:36.762 [info] [Program] Language server initialized
2025-10-02 11:37:39.764 [info] [textDocument/diagnostic] [Microsoft.CodeAnalysis.LanguageServer.DotnetCliHelper] Using dotnet executable configured on the PATH
2025-10-02 11:37:39.769 [info] [textDocument/diagnostic] [Microsoft.CodeAnalysis.LanguageServer.FileBasedPrograms.FileBasedProgramsProjectSystem] Failed to obtain virtual project for '/Users/florestankorp/Documents/Coding/WEBDEV/dotnet/Webshop/src/WebShop.Api/Contracts/Products/test.cs' using dotnet run-api. Falling back to directly creating the virtual project.
2025-10-02 11:37:39.788 [warning] [textDocument/diagnostic] [LanguageServerProjectLoader] Project /Users/florestankorp/Documents/Coding/WEBDEV/dotnet/Webshop/src/WebShop.Api/Contracts/Products/test.csproj has unresolved dependencies
2025-10-02 11:37:39.793 [info] [textDocument/diagnostic] [LanguageServerProjectLoader] Successfully completed load of /Users/florestankorp/Documents/Coding/WEBDEV/dotnet/Webshop/src/WebShop.Api/Contracts/Products/test.cs
2025-10-02 11:37:40.134 [error] [workspace/_roslyn_restore] [Microsoft.CodeAnalysis.LanguageServer.Handler.RestoreHandler] Restore completed with errors.
2025-10-02 11:37:40.146 [info] [textDocument/diagnostic] [LanguageServerProjectLoader] Completed (re)load of all projects in 00:00:01.1999756
2025-10-02 11:37:41.971 [info] [serviceBroker/connect] [WorkspaceProjectFactoryService] Project /Users/florestankorp/Documents/Coding/WEBDEV/dotnet/Webshop/src/WebShop.Infrastructure/WebShop.Infrastructure.csproj loaded by C# Dev Kit
2025-10-02 11:37:41.978 [info] [serviceBroker/connect] [WorkspaceProjectFactoryService] Project /Users/florestankorp/Documents/Coding/WEBDEV/dotnet/Webshop/tests/WebShop.Api.Tests/WebShop.Api.Tests.csproj loaded by C# Dev Kit
2025-10-02 11:37:41.982 [info] [serviceBroker/connect] [WorkspaceProjectFactoryService] Project /Users/florestankorp/Documents/Coding/WEBDEV/dotnet/Webshop/tests/WebShop.Integration.Tests/WebShop.Integration.Tests.csproj loaded by C# Dev Kit
2025-10-02 11:37:41.982 [info] [serviceBroker/connect] [WorkspaceProjectFactoryService] Project /Users/florestankorp/Documents/Coding/WEBDEV/dotnet/Webshop/src/WebShop.Api/WebShop.Api.csproj loaded by C# Dev Kit
2025-10-02 11:37:41.984 [info] [serviceBroker/connect] [WorkspaceProjectFactoryService] Project /Users/florestankorp/Documents/Coding/WEBDEV/dotnet/Webshop/src/WebShop.Domain/WebShop.Domain.csproj loaded by C# Dev Kit
2025-10-02 11:37:41.984 [info] [serviceBroker/connect] [WorkspaceProjectFactoryService] Project /Users/florestankorp/Documents/Coding/WEBDEV/dotnet/Webshop/src/WebShop.Application/WebShop.Application.csproj loaded by C# Dev Kit
2025-10-02 11:37:41.985 [info] [serviceBroker/connect] [WorkspaceProjectFactoryService] Project /Users/florestankorp/Documents/Coding/WEBDEV/dotnet/Webshop/tests/WebShop.Unit.Tests/WebShop.Unit.Tests.csproj loaded by C# Dev Kit
2025-10-02 11:38:50.885 [error] [textDocument/diagnostic] [LSP] Failed to get language for untitled:Untitled-1 with language 
2025-10-02 11:38:50.887 [error] [textDocument/diagnostic] [LSP] System.Exception: Failed to get language for textDocument/diagnostic
2025-10-02 11:38:50.891 [error] Request textDocument/diagnostic failed.
  Message: Failed to get language for textDocument/diagnostic
  Code: -32000 
[object Object]
2025-10-02 11:38:50.891 [error] Document pull failed for text document untitled:Untitled-1
  Message: Failed to get language for textDocument/diagnostic
  Code: -32000 
[object Object]

C# LSP Trace Logs log

Details

Environment Information

VSCode version: 1.104.2
C# Extension: 2.90.60
Using OmniSharp: false

Dotnet Information .NET SDK: Version: 9.0.301 Commit: a596cd22e2 Workload version: 9.0.300-manifests.9bcbba73 MSBuild version: 17.14.5+edd3bbf37

Runtime Environment:
OS Name: Mac OS X
OS Version: 15.6
OS Platform: Darwin
RID: osx-arm64
Base Path: /usr/local/share/dotnet/sdk/9.0.301/

.NET workloads installed:
There are no installed workloads to display.
Configured to use loose manifests when installing new manifests.

Host:
Version: 9.0.6
Architecture: arm64
Commit: 3875b54e7b

.NET SDKs installed:
9.0.301 [/usr/local/share/dotnet/sdk]

.NET runtimes installed:
Microsoft.AspNetCore.App 9.0.6 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.App]
Microsoft.NETCore.App 9.0.6 [/usr/local/share/dotnet/shared/Microsoft.NETCore.App]

Other architectures found:
None

Environment variables:
Not set

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
angular-console nrwl 18.70.0 nrwl.angular-console-18.70.0
angular-essentials johnpapa 18.0.0 johnpapa.angular-essentials-18.0.0
Angular2 johnpapa 18.0.2 johnpapa.angular2-18.0.2
astro-vscode astro-build 2.15.4 astro-build.astro-vscode-2.15.4-darwin-arm64
auto-close-tag formulahendry 0.5.15 formulahendry.auto-close-tag-0.5.15
auto-complete-tag formulahendry 0.1.0 formulahendry.auto-complete-tag-0.1.0
code-spell-checker streetsidesoftware 4.2.6 streetsidesoftware.code-spell-checker-4.2.6
code-spell-checker-dutch streetsidesoftware 0.5.4 streetsidesoftware.code-spell-checker-dutch-0.5.4
copilot GitHub 1.372.0 github.copilot-1.372.0
copilot-chat GitHub 0.31.3 github.copilot-chat-0.31.3
cpptools ms-vscode 1.27.7 ms-vscode.cpptools-1.27.7-darwin-arm64
csdevkit ms-dotnettools 1.50.51 ms-dotnettools.csdevkit-1.50.51-darwin-arm64
csharp ms-dotnettools 2.90.60 ms-dotnettools.csharp-2.90.60-darwin-arm64
data-workspace-vscode ms-mssql 0.6.3 ms-mssql.data-workspace-vscode-0.6.3
docker docker 0.17.0 docker.docker-0.17.0-darwin-arm64
dupchecker jianbingfang 0.1.7 jianbingfang.dupchecker-0.1.7
EditorConfig EditorConfig 0.17.4 editorconfig.editorconfig-0.17.4
errorlens usernamehw 3.26.0 usernamehw.errorlens-3.26.0
explorer vitest 1.30.0 vitest.explorer-1.30.0
gc-excelviewer GrapeCity 4.2.64 grapecity.gc-excelviewer-4.2.64
gitlens eamodio 17.5.1 eamodio.gitlens-17.5.1
go golang 0.50.0 golang.go-0.50.0
grafana-alloy Grafana 0.2.0 grafana.grafana-alloy-0.2.0
hexeditor ms-vscode 1.11.1 ms-vscode.hexeditor-1.11.1
html-css-class-completion Zignd 1.20.0 zignd.html-css-class-completion-1.20.0
LiveServer ritwickdey 5.7.9 ritwickdey.liveserver-5.7.9
material-icon-theme PKief 5.27.0 pkief.material-icon-theme-5.27.0
ng-template Angular 20.2.2 angular.ng-template-20.2.2
output-colorizer IBM 0.1.2 ibm.output-colorizer-0.1.2
playwright ms-playwright 1.1.15 ms-playwright.playwright-1.1.15
prettier-vscode esbenp 11.0.0 esbenp.prettier-vscode-11.0.0
pretty-ts-errors YoavBls 0.6.1 yoavbls.pretty-ts-errors-0.6.1
properties-validator vivek-kasture 0.0.6 vivek-kasture.properties-validator-0.0.6
rainbow-csv mechatroner 3.22.0 mechatroner.rainbow-csv-3.22.0
remote-containers ms-vscode-remote 0.429.0 ms-vscode-remote.remote-containers-0.429.0
remote-explorer ms-vscode 0.5.0 ms-vscode.remote-explorer-0.5.0
remote-server ms-vscode 1.5.3 ms-vscode.remote-server-1.5.3
remote-ssh ms-vscode-remote 0.120.0 ms-vscode-remote.remote-ssh-0.120.0
remote-ssh-edit ms-vscode-remote 0.87.0 ms-vscode-remote.remote-ssh-edit-0.87.0
remote-wsl ms-vscode-remote 0.104.3 ms-vscode-remote.remote-wsl-0.104.3
sonarlint-vscode SonarSource 4.31.0 sonarsource.sonarlint-vscode-4.31.0-darwin-arm64
svelte-vscode svelte 109.11.1 svelte.svelte-vscode-109.11.1
terraform hashicorp 2.37.2 hashicorp.terraform-2.37.2-darwin-arm64
vscode-azureappservice ms-azuretools 0.26.4 ms-azuretools.vscode-azureappservice-0.26.4
vscode-azureresourcegroups ms-azuretools 0.11.4 ms-azuretools.vscode-azureresourcegroups-0.11.4
vscode-containers ms-azuretools 2.2.0 ms-azuretools.vscode-containers-2.2.0
vscode-counter uctakeoff 3.7.2 uctakeoff.vscode-counter-3.7.2
vscode-css-formatter aeschli 1.0.2 aeschli.vscode-css-formatter-1.0.2
vscode-diff fabiospampinato 2.1.2 fabiospampinato.vscode-diff-2.1.2
vscode-docker ms-azuretools 2.0.0 ms-azuretools.vscode-docker-2.0.0
vscode-dotnet-runtime ms-dotnettools 2.3.7 ms-dotnettools.vscode-dotnet-runtime-2.3.7
vscode-eslint dbaeumer 3.0.16 dbaeumer.vscode-eslint-3.0.16
vscode-github-actions github 0.27.2 github.vscode-github-actions-0.27.2
vscode-icons vscode-icons-team 12.14.0 vscode-icons-team.vscode-icons-12.14.0
vscode-jest Orta 6.4.4 orta.vscode-jest-6.4.4
vscode-jest-runner firsttris 0.4.84 firsttris.vscode-jest-runner-0.4.84
vscode-pylance ms-python 2025.8.3 ms-python.vscode-pylance-2025.8.3
vscode-remote-extensionpack ms-vscode-remote 0.26.0 ms-vscode-remote.vscode-remote-extensionpack-0.26.0
vscode-speech ms-vscode 0.16.0 ms-vscode.vscode-speech-0.16.0-darwin-arm64
vscode-sqlite alexcvzz 0.14.1 alexcvzz.vscode-sqlite-0.14.1
vscode-stylelint stylelint 1.5.3 stylelint.vscode-stylelint-1.5.3
vscode-svgviewer cssho 2.0.0 cssho.vscode-svgviewer-2.0.0
vscode-tailwindcss bradlc 0.14.26 bradlc.vscode-tailwindcss-0.14.26
vscode-xml redhat 0.29.0 redhat.vscode-xml-0.29.0-darwin-arm64
vscode-yaml redhat 1.19.0 redhat.vscode-yaml-1.19.0
C# Settings
Setting Value
preferCSharpExtension false
compilerDiagnosticScope openFiles
analyzerDiagnosticScope openFiles
enableXamlTools true
useServerGC true
System Info
Item Value
CPUs Apple M2 Pro (10 x 2400)
GPU Status 2d_canvas: enabled
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, 6, 6
Memory (System) 16.00GB (0.31GB free)
Process Argv
Screen Reader no
VM 0%

Metadata

Metadata

Assignees

No one assigned

    Labels

    untriaged

    Type

    No type

    Fields

    No fields configured for issues without a type.

    Projects

    No projects

    Milestone

    No milestone

    Relationships

    None yet

    Development

    No branches or pull requests

    Issue actions