It's not as simple as "it can only be x" - there's a lot of potential issues. It could be a corrupted jobs.db, or a failing hard drive, bad ram, malware, or you might be using an old/buggy version of Ketarin - or it could be an incompatible OS language or a "broken" app file.   To repair the jobs.db file: You might also want to try a vacuum on the database with SQLite directly: sqlite3 jobs.db "VACUUM;"   To test the drive: install SmartMonTools, then in an elevated cmd prompt run: smartctl -a sda Big numbers are bad.   To test the ram: download memtest86+, burn the ISO to cd and boot with it. Let it run at least 2 complete passes. You'll know if there are errors.   Malware is way beyond the scope of this forum.   The language thing has hit a couple users. If you're not using an English-based OS or app xml files then it's possible that copy & pasting or importing the app data has corrupted the jobs.db. This can also happen if you're using an English or UTF-capable OS but the app xml file was saved as only 8-bit or simple ASCII and it had hi-bit characters in it (which can happen if it was copy & pasted from the forum, for example). Unfortunately, there's really no way to fix this cleanly. You'll need to track down exactly which app file is causing you problems and fix it yourself. It's also a good idea to use a text editor (like Notepad++) that behaves well with UTF-8 to ensure that this kind of thing doesn't happen.