This maybe caused nothing but unaccesable recent project or files.
Most probably the files targeted from a cloud directory for example microsoft one drive.
If you uninstall and reinstall the Autocad Eagle PCB, the problem will still remain.
The solution is deleting the application’s “mind”.
So go your C:\USERS\CurrentUser directory, make sure you can see hidden directories and find AppData\Roaming directories.
Find CadSoft and Eagle directories on there and delete both of them.
And now you can reinstall your Eagle PCB!