Thanks for your help. I appreciate it.
I ran the FCP Rescue for a couple of times to be sure (restarted computer too) but it didn’t help.
Trying creating a new project, the same thing.
The weird thing is that I can still play my old projects just fine, even copy and paste files from one project to another.
Somehow my FCP just doesn’t import any files at all.
(doesn’t even import old .mov files that still play fine on FCP when I open an old project)
Exporting works fine.