Error message when trying to save new content to TM after installing latest Studio 2017 SR1 CU15

I installed the latest service release Studio 2017 SR1 CU15 yesterday and have had massive problems working with studio since then. Every time I try to confirm a segment and move to the next one, Studio freezes and after literally minutes displays the following error message:

An error has occurred while using the translation provider: The translation memory data file engine returned an error: database is locked.

I double-checked that the location of the TM I want to use is correct and can be accessed, it is also possible to search for terms in the TM (concordance search). Still I am not able to save any new texts to the TM - I also get an error message when trying to finalize a file (the "Update Main Translation Memories" batch task fails).

Is anyone familiar with this problem or gets the same error message?

Christina