For about 2 weeks now, after Tixati runs for a while I can't open completed downloads. After double clicking on the completed file nothing happens. When I go to X out of the program it stops responding. After restarting Tixati it opens the completed torrents again for a bit. I have already reinstalled. Any suggestions?

Could be a problem with the external program you use to open those files, file association, that kind of thing.

Does it happen with only a specific type of file (films, music, archives, etc), or specific file extension (mpeg, mp3, zip, etc), or with everything you're trying to open from inside Tixati (if you only usually download a specific kind of files, might be worth it trying different kinds just as a test) ?

Can you open the same files normally at all times from outside Tixati ?

Another possibility could be interference from a security program thinking that something in your system is trying to hijack something else - you could try and disable your antivirus to see if the problem persists.