Studio 2021 crashes on saving

Hi folks,

starting today I receive a message 

Users\name\OneDrive\Documents\Studio 2021\AutoSave\<long numer>

and Studio closes, leaving me with the pop-up. I have tried several solutions but nothing worked
disable synchronization to onedrive
disable auto-save
remove the autosave folder
several reboots.
The problem does not only occur on auto-save but also on Ctrl+s

Any ideas? It is pretty urgent.
Thanks in advance

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