Recently I had this warning start popping up when using Pokertracker3: "Unable to begin feeder import process. Reason: Unsupported database type: PokerTracker 3 Database ()"
I tried different suggestions in this forum relating to the same incident and seemed to have no luck. Restarting the server didn't work because it was already running, so I decided to look into what files my hand histories were saving to according to full tilt itself, and also seeing what they lined up with in PT3. This has NOTHING to do with PostgreSQL not running. It is also unnecessary to uninstall/reinstall PostgreSQL.
After snooping around I found that recently full tilt had created another folder within the HandHistory folder that PT3 draws data from. The original subfolder, "Full Tilt" was still there with all previous HHs included, but another titled "LMac789" had been created (who knows how), including all of the tables which hadn't been loading in the HUD when the problem originally started. It also contained all histories for the tables that I had played once the HUD had stopped working entirely. This could explain issues with the database because it can't decide which of the two folders to add additional data from.
All I had to do to fix this issue was create a new folder which histories are saved to from full tilt itself (Options>HandHistory...>Change Folder>New Folder (at new destination)) and then change which folder PT3 draws data from to that new folder. PT3 informed me that "full tilt is not set up to use this folder". It lies, click accept/yes anyway. HUD works flawlessly again and all previous hands from the old folder/imports are still included in the HUD, avoiding any head aches associated with re-entering old histories.
I couldn't find any updates on an actual fix to this problem so I figured I'd post just in case. Hope this helps.