Microsoft has confirmed that it is aware of the update issue KB4535996

Many are aware of the issues with the KB4535996 update for Windows 10. After installation (if it even happens), there may be to appear blue screen errors, slower boot times, and reduced FPS in games. There have also been reported failures in SignTool, File Explorer, Task Manager, the desktop, and more. The update did not spare even sleep mode. 

These shortcomings have been noted for quite some time. However, only now has Microsoft partially confirmed acknowledged their existence and promised that a fix will be available by mid-March. Specifically, this concerns only the issues with SignTool, BSOD, as well as slow boot and performance problems. However, there is currently no temporary solution, so users must wait for the new patch.

At this time, Redmond recommends uninstalling KB4535996, after which you should go to the 'Updates and Security' section in the system and pause updates for 7 days. It is expected that this will allow everything to return to normal.

Ironically, the KB4535996 patch was supposed to fix several issues with Windows search, but it introduced new failures. We can only hope that future updates are not as problematic. However, the release version of Windows 10 (2004) is still ahead.

Source: 3dnews.ru