[Bug] WAM Error 0, Internal Error Code 540940121

[CarlT789]

Library version used

unknown

.NET version

This happened when I started VS 2026 and opened a C++ project.

This error was not from our app/project, but from VS 2026, v18.4.1

Scenario

Other - please specify

Is this a new or an existing app?

The app is in production, I haven't upgraded MSAL, but started seeing this issue

Issue description and reproduction steps

This error happened when I started VS 2026 and opened a project. It was not from our project.

"TF30063: You are not authorized to access <our_page>.visualstudio.com<our_page>" showed up in the output window. When I tried to authenticate, I got a dialog displaying a WAM error.
Error code:0
Error Message: Account has previously been signed out of this application.
Internal Error Code 540940121

I was presented with the option to Continue or Cancel. I pressed Continue, and I appeared to get properly logged in - I could access the NuGet package information.

Relevant code snippets

Expected behavior

Not getting an error.

Identity provider

Microsoft Entra ID (Work and School accounts and Personal Microsoft accounts)

Regression

No response

Solution and workarounds

No response

[github-actions]

Here are some similar issues that might help you. Please check if they can solve your problem.

• Unable to Sign in (Visual Studio) #4914
• [Bug] WAM credentials error 3399680404, 55793641 #5479
• [Bug] WAM Error - Account has previously been signed out of this application. #4977

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Possible solution (Extracted from existing issue, might be incorrect; please verify carefully)

Solution 1:

The issue has been fixed with Microsoft.Identity.Client.NativeInterop package version 0.17.0.

Reference:

• Unable to Sign in (Visual Studio) #4914 (comment)

Solution 2:

Upgrade to Visual Studio Version 17.12. There was a fix released about a month back that addressed an issue with very similar symptoms.

Reference:

• [Bug] WAM Error - Account has previously been signed out of this application. #4977 (comment)
• [Bug] WAM Error - Account has previously been signed out of this application. #4977 (comment)

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