Failed to attach to .NET process with error 0x80070057 during "configurationDone"

[KaviyaPriya-R]

Hi Team,

I'm unable to debug a .NET 9 web app using the ".NET Core Attach" configuration with a hardcoded process ID. The attach succeeds initially (DAP module/thread events load), but fails at the configurationDone step with CodeExpectedError: Failed command 'configurationDone' : 0x80070057 (E_INVALIDARG). Symbol also not load for the app DLL after a Debug rebuild.

Error:

workbench.desktop.main.js:665265 CodeExpectedError: Failed command 'configurationDone' : 0x80070057
    at RawDebugSession2.handleErrorResponse (workbench.desktop.main.js:567559:20)
    at workbench.desktop.main.js:567540:50
    at async sendConfigurationDone (workbench.desktop.main.js:568406:13)
    at async UniqueContainer.value (workbench.desktop.main.js:568417:9)
onDidChangeNotification	@	workbench.desktop.main.js:665265

Environment

OS: Windows 11 (64-bit).
.NET SDK: 9.0.305 (dotnet --version).
DotRush Extension: 25.10.282.
netcoredbg: 3.1.2-1054 (global install).
Project: ASP.NET Core Web App (.NET 9).
Run as: Administrator (both app and IDE).

Attempts/Fixes Tried

Rebuilt in Debug mode
Matched privileges (admin mode).
Hardcoded PID in launch.json.
Enabled verbose logging (debug.console.level: "verbose" in settings.json).
Tested minimal console app (dotnet new console)—same error.

Additional Context

App runs fine via dotnet run; PID is valid .NET process (x64).
No issues in launch mode (request: "launch").

Thanks for the help—looking forward to a fix!

[gbalykov]

Please try to attach using CLI mode from terminal without IDE