LrC Import doesn't find existing photos

Hello,

I try to import files into LrC from the Download folder, but doesn't show them.

The import worked for several months normally, sometimes it already showed this problem. But after restarting it was fixed. But know the problem is stable, the import doesn't work with anything - whether a different folder, nor a conncected device.

I'm working with Mac OS Catalina, LrC 10.0, and LrC has granted full access to the hard disk, so this couldn't be the source of the problem.

Has anybody an idea to solve this?

Thx! Gab