I may assume that if you change folder names in Finder, that will screw up Projects because the image references back the source Folder. Wish I knew that. This just happened but I don’t remember what the names were that I changed them from. Is there any way to fix this?
If you rename items in Finder while PhotoLab is closed, DPL will later simply add the renamed items as new, which makes DPL’s catalog drift away from what is actually stored on your drive…and DPL has no feature to fix such drifts.
If you’d now rename the folders back to the original names, the wrong names remain in DPL’s database and searching for items will then provide false positives (find inexistent items).
That being said, you can find the original folder names if you are willing/able to dig into the database with a DB viewer. It might be much simpler to find the old names in a backup though.
If you are running Time Machine, you can try renaming your folders back in Finder and then restore the three database files in Time Machine.
In fact, you could always try reverting the file names and folders using Time Machine.