[Software] Windows 11 update install failures are reportedly happening again – and it’s breaking the built-in antivirus

[Vinicius™]

 

Windows 11 has reportedly run into problems with its latest cumulative update, with the upgrade failing to install for some folks, and breaking Microsoft Defender in other cases.

 

Windows Latest has rounded up the latest batch of complaints regarding a cumulative update for Windows 11, in this case KB5029263, which is the mandatory upgrade for August.

 

As mentioned, some users are reporting installation failures with KB5029263, and the other annoyance here is that the failed update keeps offering itself over and over, constantly lurking as a red dot (update pending warning) on the taskbar (system tray).

 

Readers of Windows Latest have complained directly to the tech site about this, and there are affected Windows 11 users venting on Microsoft’s Feedback Hub.

 

On the Feedback Hub there are also scattered complaints of some more serious gremlins in the works with this August update. That includes the update getting stuck before it completes (and getting stuck again on subsequent installation attempts), and also File Explorer failing to work (meaning you can’t explore folders on the desktop).

 

KB5029263 is apparently also messing with Microsoft Defender, Windows 11’s built-in security app – which now ranks pretty highly among the best free antivirus – in some cases. Some users are seeing the following error when opening the app: ‘Unable to log into Microsoft Defender.’