UAC not showing and desktop frozen when File Explorer needs an elevation, forcing a cold reboot

Hello there! I am Charity, I'm an Independent Advisor. I'm glad to help you today!

My apologies about that. let's try to automatically repair corrupted system files.

Press Windows + R, type msconfig, and press Enter.

In the System Configuration window, go to the Services tab.

Check Hide all Microsoft services, then click Disable all.

Go to the Startup tab and click Open Task Manager.

In Task Manager, disable all startup items.

Close Task Manager, then click OK in System Configuration.

Restart your computer.

Then, open Command Prompt as an administrator by right-clicking the Start button and selecting "Command Prompt (Admin)." In the Command Prompt window, type sfc /scannow and press Enter. Wait for the scan to complete; this process might take some time, and the tool will automatically attempt to fix any detected issues. Once the scan is finished, restart your computer.

Next, open Command Prompt as an administrator again. In the Command Prompt window, type DISM /Online /Cleanup-Image /RestoreHealth and press Enter. Wait for the process to complete, as it might also take some time to repair the Windows image. Once the DISM process is complete, restart your computer.

After completing these steps, try launching your applications again to see if the issue is resolved.

Kind Regards,
Charity

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Please note that things might need more than one reply to completely resolve your issue, as it will completely depend on the complexity of the question and the amount of detail that you have provided me.

Hi Charity,

SFC and DISM did not find any errors (build is 26100.2152) and yet the problem is still there.

Regards.

Thank you for the information. Are you still able to do a rollback?

Open Settings by pressing Windows + I.

Go to Update & Security, then select View Update History.

Click Uninstall updates and find the most recent update (look at the date).

Right-click on it and choose Uninstall, then restart your computer.

To pause future updates:

In Update & Security, select Pause updates for 7 days to prevent the update from reapplying automatically. You can extend this period in Advanced options.

Hello,

I am not able to do a rollback.

I am experienceing this problem since build 26100.1742 and the latest build (26100.2152) was installed by updating the entire OS with an ISO and the previous install has been cleaned with cleanmgr.

Regards.

Thank you for the confirmation. Let's try something else.

Press Windows + R, type msconfig, and press Enter.

In the System Configuration window, go to the Services tab.

Check Hide all Microsoft services, then click Disable all.

Go to the Startup tab and click Open Task Manager.

In Task Manager, disable all startup items.

Close Task Manager, then click OK in System Configuration.

Restart your computer.

Then, Go to Control Panel > User Accounts > Change User Account Control settings, and move the slider down to the lowest setting.

Note that this reduces security prompts, so you might want to revert it after troubleshooting.

I don't want to disable UAC.

But I found the culprit, it's actually a known bug in 24H2.

I am using Windows Hello with my fingerprint reader to authenticate, and this is what is probably what is causing the problem to UAC:
Windows 11, version 24H2 known issues and notifications | Microsoft Learn

I guess I will have to wait until Microsoft fixes 24H2.

Regards.