There’s a bug in Windows 11 that prevents users from signing in after adding new Microsoft accounts. According to Microsoft, it is caused by the KB5016691 update, which rolled out in preview on August 25, 2022. The company quickly addressed the problem and provided detailed insights.

“After installing KB5016691 and adding a new Microsoft account user in Windows, you might be unable to sign in for a brief time after the first restart or sign out. The issue only affects the newly added Microsoft account user and only for the first sign in,” Microsoft said. 

Thankfully, Microsoft assured everyone affected that the problem would be over “after a brief time.” Furthermore, it said that it only concerns “the newly added Microsoft account user and only for the first sign in.” Active Directory domain users accounts or Azure Active Directory accounts are also not affected by the bug, which is a relief.

To finally end it, Microsoft announced that it would release the Known Issue Rollback, which should change back the buggy Windows fixes earlier rolled out. It won’t take more than 24 hours, which means the issue of affected consumer and non-managed business devices should be resolved before the weekend. Microsoft also suggested restarting your machines in order to help with the resolution being pushed now.

As for the enterprise-managed devices, IT admins should work on a KIR Group Policy to solve this. “The special Group Policy can be found in Computer Configuration -> Administrative Templates -> KB5016691 220722_051525 Known Issue Rollback -> Windows 11 (original release),” explained Microsoft and offered the link where the Rollback Group Policy for Windows 11 V 21H2 can be downloaded. The company also provides a support document detailing how to use Group Policy to deploy a Known Issue Rollback.

https://mspoweruser.com/microsoft-addresses-issue-preventing-windows-logins/