Request textDocument/formatting failed - End: (1264,13) matches or exceeds SourceText boundary 1266

[NatthaphonAkkarapichet]

Type: Bug

Issue Description

Steps to Reproduce

Expected Behavior

Actual Behavior

Extension version: 2.131.79
VS Code version: Code 1.113.0 (cfbea10c5ffb233ea9177d34726e6056e89913dc, 2026-03-24T15:07:18+01:00)
OS version: Windows_NT x64 10.0.26200
Modes:

Logs

C# log

Details

2026-03-29 11:04:07.309 [info] Locating .NET runtime version 10.0.5
2026-03-29 11:04:07.436 [info] Dotnet path: C:\Program Files\dotnet\dotnet.exe
2026-03-29 11:04:07.436 [info] Activating C# + C# Dev Kit...
2026-03-29 11:04:07.788 [info] info: Program[0]
2026-03-29 11:04:07.788 [info]       Server started with process ID 46428
2026-03-29 11:04:14.891 [info] [Program] Language server initialized
2026-03-29 11:04:15.021 [info] [Program] Monitoring client process 17676 for exit
2026-03-29 11:04:23.259 [info] [serviceBroker/connect] [WorkspaceProjectFactoryService] Project D:\CorporateWork\StinHR\StinHR\StinHR.csproj loaded by C# Dev Kit
2026-03-29 15:30:50.261 [error] Request textDocument/formatting failed.
  Message: End: (1264,13) matches or exceeds SourceText boundary 1266.
  Code: -32000 
[object Object]

C# LSP Trace Logs log

Details

Environment Information

VSCode version: 1.113.0
C# Extension: 2.131.79
Using OmniSharp: false

Dotnet Information

.NET SDK: Version: 10.0.201 Commit: 4d3023de60 Workload version: 10.0.200-manifests.34a88a22 MSBuild version: 18.3.0-release-26153-122+4d3023de6

Runtime Environment:
OS Name: Windows
OS Version: 10.0.26200
OS Platform: Windows
RID: win-x64
Base Path: C:\Program Files\dotnet\sdk\10.0.201\

.NET workloads installed:
[ios]
Installation Source: VS 18.5.11612.153, VS 17.14.37111.16
Manifest Version: 26.2.10217/10.0.100
Manifest Path: C:\Program Files\dotnet\sdk-manifests\10.0.100\microsoft.net.sdk.ios\26.2.10217\WorkloadManifest.json
Install Type: Msi

[android]
Installation Source: VS 18.5.11612.153, VS 17.14.37111.16
Manifest Version: 36.1.43/10.0.100
Manifest Path: C:\Program Files\dotnet\sdk-manifests\10.0.100\microsoft.net.sdk.android\36.1.43\WorkloadManifest.json
Install Type: Msi

[maui-windows]
Installation Source: VS 18.5.11612.153, VS 17.14.37111.16
Manifest Version: 10.0.20/10.0.100
Manifest Path: C:\Program Files\dotnet\sdk-manifests\10.0.100\microsoft.net.sdk.maui\10.0.20\WorkloadManifest.json
Install Type: Msi

[maccatalyst]
Installation Source: VS 18.5.11612.153, VS 17.14.37111.16
Manifest Version: 26.2.10217/10.0.100
Manifest Path: C:\Program Files\dotnet\sdk-manifests\10.0.100\microsoft.net.sdk.maccatalyst\26.2.10217\WorkloadManifest.json
Install Type: Msi

Configured to use workload sets when installing new manifests.
No workload sets are installed. Run "dotnet workload restore" to install a workload set.

Host:
Version: 10.0.5
Architecture: x64
Commit: a612c2a105

.NET SDKs installed:
7.0.403 [C:\Program Files\dotnet\sdk]
8.0.100 [C:\Program Files\dotnet\sdk]
8.0.407 [C:\Program Files\dotnet\sdk]
9.0.203 [C:\Program Files\dotnet\sdk]
9.0.312 [C:\Program Files\dotnet\sdk]
10.0.201 [C:\Program Files\dotnet\sdk]

.NET runtimes installed:
Microsoft.AspNetCore.App 6.0.25 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 6.0.36 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 7.0.13 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 7.0.14 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 8.0.0 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 8.0.14 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 8.0.25 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 9.0.4 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 9.0.14 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 10.0.5 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.NETCore.App 6.0.25 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 6.0.36 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 7.0.13 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 7.0.14 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 8.0.0 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 8.0.14 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 8.0.25 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 9.0.3 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 9.0.4 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 9.0.14 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 10.0.5 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.WindowsDesktop.App 6.0.25 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
Microsoft.WindowsDesktop.App 6.0.36 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
Microsoft.WindowsDesktop.App 7.0.13 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
Microsoft.WindowsDesktop.App 7.0.14 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
Microsoft.WindowsDesktop.App 8.0.0 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
Microsoft.WindowsDesktop.App 8.0.14 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
Microsoft.WindowsDesktop.App 8.0.25 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
Microsoft.WindowsDesktop.App 9.0.3 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
Microsoft.WindowsDesktop.App 9.0.4 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
Microsoft.WindowsDesktop.App 9.0.14 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
Microsoft.WindowsDesktop.App 10.0.5 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]

Other architectures found:
x86 [C:\Program Files (x86)\dotnet]
registered at [HKLM\SOFTWARE\dotnet\Setup\InstalledVersions\x86\InstallLocation]

Environment variables:
DOTNET_CLI_UI_LANGUAGE [en-US]

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
askia-qexml-generator-extension	Askia	1.0.1	askia.askia-qexml-generator-extension-1.0.1
asp-net-core-switcher	adrianwilczynski	2.0.2	adrianwilczynski.asp-net-core-switcher-2.0.2
auto-close-tag	formulahendry	0.5.15	formulahendry.auto-close-tag-0.5.15
auto-rename-tag	formulahendry	0.1.10	formulahendry.auto-rename-tag-0.1.10
blazorwasm-companion	ms-dotnettools	1.1.4	ms-dotnettools.blazorwasm-companion-1.1.4
code-spell-checker	streetsidesoftware	4.5.6	streetsidesoftware.code-spell-checker-4.5.6
color-highlight	naumovs	2.8.0	naumovs.color-highlight-2.8.0
copilot-chat	GitHub	0.41.2	github.copilot-chat-0.41.2
csdevkit	ms-dotnettools	3.10.4	ms-dotnettools.csdevkit-3.10.4-win32-x64
csharp	ms-dotnettools	2.131.79	ms-dotnettools.csharp-2.131.79-win32-x64
docker-vscode-extension	docker	0.0.6	docker.docker-vscode-extension-0.0.6
errorlens	usernamehw	3.28.0	usernamehw.errorlens-3.28.0
es7-react-js-snippets	rodrigovallades	1.9.3	rodrigovallades.es7-react-js-snippets-1.9.3
gitlens	eamodio	17.11.1	eamodio.gitlens-17.11.1
i18n-ally	lokalise	2.13.1	lokalise.i18n-ally-2.13.1
JavaScriptSnippets	xabikos	1.8.0	xabikos.javascriptsnippets-1.8.0
jsoncrack-vscode	AykutSarac	5.0.0	aykutsarac.jsoncrack-vscode-5.0.0
labs-ai-tools-vscode	docker	0.1.11	docker.labs-ai-tools-vscode-0.1.11
path-intellisense	christian-kohler	2.10.0	christian-kohler.path-intellisense-2.10.0
prettier-vscode	esbenp	12.4.0	esbenp.prettier-vscode-12.4.0
prisma	Prisma	31.7.0	prisma.prisma-31.7.0
rainbow-csv	mechatroner	3.24.1	mechatroner.rainbow-csv-3.24.1
remote-containers	ms-vscode-remote	0.447.0	ms-vscode-remote.remote-containers-0.447.0
remote-wsl	ms-vscode-remote	0.104.3	ms-vscode-remote.remote-wsl-0.104.3
rust-analyzer	rust-lang	0.3.2836	rust-lang.rust-analyzer-0.3.2836-win32-x64
sonarlint-vscode	SonarSource	4.45.0	sonarsource.sonarlint-vscode-4.45.0-win32-x64
sqltools	mtxr	0.28.5	mtxr.sqltools-0.28.5
Vite	RuiGe24601	0.0.4	ruige24601.vite-0.0.4
volar	Vue	3.2.6	vue.volar-3.2.6
vscode-containers	ms-azuretools	2.4.1	ms-azuretools.vscode-containers-2.4.1
vscode-docker	ms-azuretools	2.0.0	ms-azuretools.vscode-docker-2.0.0
vscode-dotnet-runtime	ms-dotnettools	3.0.0	ms-dotnettools.vscode-dotnet-runtime-3.0.0
vscode-edit-csv	janisdd	0.11.8	janisdd.vscode-edit-csv-0.11.8
vscode-entity-framework	richardwillis	0.0.20	richardwillis.vscode-entity-framework-0.0.20
vscode-eslint	dbaeumer	3.0.24	dbaeumer.vscode-eslint-3.0.24
vscode-icons	vscode-icons-team	12.17.0	vscode-icons-team.vscode-icons-12.17.0
vscode-thunder-client	rangav	2.39.13	rangav.vscode-thunder-client-2.39.13
vscode-typescript-next	ms-vscode	6.0.20260324	ms-vscode.vscode-typescript-next-6.0.20260324
vscode-yaml	redhat	1.21.0	redhat.vscode-yaml-1.21.0
vue-peek	dariofuzinato	1.0.2	dariofuzinato.vue-peek-1.0.2
vue-snippets	hollowtree	1.0.4	hollowtree.vue-snippets-1.0.4

C# Settings

Setting	Value
preferCSharpExtension	false
compilerDiagnosticScope	openFiles
analyzerDiagnosticScope	openFiles
enableXamlTools	true
useServerGC	true

System Info

Item	Value
CPUs	AMD Ryzen 7 6800H with Radeon Graphics (16 x 3194)
GPU Status	2d_canvas: enabled GPU0: VENDOR= 0x10de, DEVICE=0x2560 [NVIDIA GeForce RTX 3060 Laptop GPU], DRIVER_VENDOR=NVIDIA, DRIVER_VERSION=32.0.15.9186 ACTIVE GPU1: VENDOR= 0x1002, DEVICE=0x1681 [AMD Radeon(TM) Graphics], DRIVER_VERSION=31.0.21024.2004 GPU2: VENDOR= 0x1414, DEVICE=0x008c [Microsoft Basic Render Driver], DRIVER_VERSION=10.0.26100.7309 Machine model name: Machine model version: 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: disabled_off trees_in_viz: disabled_off video_decode: enabled video_encode: enabled webgl: enabled webgl2: enabled webgpu: enabled webnn: disabled_off
Load (avg)	undefined
Memory (System)	31.19GB (8.97GB free)
Process Argv	--crash-reporter-id 4f57296a-528d-4307-969c-7e69b3fb679e
Screen Reader	no
VM	0%

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vsliv368:30146709
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nativeloc1:31344060
dwcopilot:31170013
dwoutputs:31242946
copilot_t_ci:31333650
e5gg6876:31282496
pythonrdcb7:31342333
6518g693:31463988
aj953862:31281341
4f60g487:31327383
63221493:31336333
envsactivate1:31464700
cloudbuttont:31379625
aihoversummaries_t:31469308
3efgi100_wstrepl:31403338
839jf696:31457053
use-responses-api:31390855
je187915:31454425
ec5jj548:31422691
cp_cls_t_966_ss:31454198
a9239246:31483273
4je02754:31466945
c3h7c220:31478652
ge8j1254_inline_auto_hint_haiku:31427726
38bie571_auto:31426784
cp_cls_c_1081:31454833
ia-use-proxy-models-svc:31452481
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test_treatment2:31471001
g_63ac8346:31467999
idci7584:31464702
e3e4d672:31461204
showingstats:31481873
534a6447_copy:31478748
7ef87755:31458076
chat:31457767
8hig5102:31480529
67jbj424:31484169
bg_compact_t:31481650
t-some:31484756
cpptoolsoff-v2:31475362
827if375:31477818
db0gd219:31481871
ddid_c:31478207
getcmakediagnosticson:31483360
jah3f675:31485061
nes-perm-reb-0:31481661

[dibarbet]

@NatthaphonAkkarapichet when you encountered this error - do you remember what kind of file you had open (e.g. .cs or .razor)? If you would be able to share the file that would be helpful, alternatively if you can reproduce the problem, it would be helpful to record the activity logs as described here - https://github.com/dotnet/vscode-csharp/blob/main/SUPPORT.md#capturing-activity-trace-logging