Lightroom classic unable to import pictures and crashes

hi, very unfortunately I've updated on the weekend LRC from 13.x to 14.0.1. Since the upgrade I'm no longer able to import pictures into the katalog. (pictures already on the harddisk). When selecting a single digit number of pictures it could happen that they get loaded. but if I select a couple of directories with in total ~50 pic the system comes to a hold. the Task picture import is starting but no progress.

When I cancel the tasks a dialog box is coming up which says something like "no pictures found to import".

When closing LRC I'm no longer able to restart it. 

When looking to the MS task manager than it is full of Adobe tasks running.

My PC is running on MS Windows 10 home - most current version

Only when rebooting the machine I'm able again to launch LRC. I can work with it. the catalog has been migrated but if I try to import picture the problem happens again.... So it is reproducable unfortunately.

Thanks for any good idea how to overcome the problem. I would wish I could go back to V13.x ...