Hello Maxstar,
thanks that you are willing to help me.
Log from setupdiag shows only one older error from 18th February which is about Bitlocker. Nothing from the installations of the comulative updates I tried a few more times since 18th February.
I must say, that I don't use Bitlocker on any of my drives, and I also don't intend to use Bitlocker in the future. But I found out, that there is indeed a problem with Bitlocker on my system.
If I go to settings/system/info and then click on Bitlocker-Settings under related settings on the right side, after a few seconds the settings window closes automatically, without showing the Bitlocker-settings from cotrol-panel. Also is Bitlocker icon missing from control-panel. But under services the Bitlocker-service shows up and is set to automatic.
Can the non working bitlocker-settings be the problem for the failing updates?