Sounds like you have database corruption. There are two directories (which hold your bins, parts in the mine parts bin and the parts database) in
on the Mac. They are not cleared during a reinstall to preserve your parts during an upgrade. The first thing I would try is make a copy of both directories for safety (Fritzing will recreate the directories if they are not there, and will access the old ones if they are replaced) and then try a database rebuild by starting Fritzing and select any window except Welcome (i.e. breadboard, schematic or pcb) and then click Part->Regenerate parts database. This will process for a while (regenerating the sql database) and then exit Fritzing. If the errors still occur when you restart Fritzing then delete the two directories (making sure you still have copies elsewhere) and then restart Fritzing. It will recreate both directories when it starts and should then do a parts update, which means it appears to hang for a while (for me it is usually a minute or so) while it clones the parts repository from github. Interrupting it at this point usually causes database corruption, so wait for it to complete and tell it OK when it wants to do a parts update to get the latest parts (as with the rebuild, it will process then exit Fritzing to complete the rebuild of the database). That should fix the parts database assuming you are not running in to the bug in the listing, but then you will need to reload your mine parts either from the saved directories or by loading the .fzz files and dragging the parts not in core from the temp parts bin that is loaded from the fzz file in to the mine parts bin (that is probably the easiest way, but copying from the saved directories will also work but is a bit more complex). The fzz files will as noted have any of the parts that were in the mine parts bin in the temp bin and should load as normal once the parts database is OK, so if you only want to access the sketches you shouldn’t need to recreate the mine parts bin if you don’t want to.