can't save or open Files with apple-apps, in specific folders
Good morning.
Since several days, my macBook Air (mid 12, MacOs 10.15.1) can't save or open (certain) files.
Every time I want to open, delete, drag'n drop a file located in ~/Desktop, ~/iCloud drive, ~/Documents, in Pages or Preview, it complains with something like
"document (document_name.suffix) couldn't be opened"
Pages couldn't read the document
I can open a file located in one of those folders with 3rd-party applications (Affinity Publisher, Coda for example).
I can copy a file and paste it into a place other than the above mentioned folders,
but I can not not drag-drop it.
As far as I can see, this problem is concerning Pages, Preview, Numbers, ..., and the 3 folders named above.
What's wrong?
How to fix this?
MacBook Air 13", macOS 10.15