I had the same problem with Synthi (CZ was fine). I also noticed that there was no Synthi patch in Analog Lab. Reinstalling both Synthi and Analog Lab did not help.
However, removing the db.db3 file as suggested above (renamed it to be safe) solved the problem for me.
After that, Analog Lab came up empty and started to rebuild the data. It took about a minute on my computer for all the instruments to reappear, one by one.
Hope this help