I'm not sure if it's related to calibre and the lovely new kobo touch driver, but I'm having database issues now. I've done nothing except use calibre to load books, sync touch over wifi and switch kobo off and on. (The off and on switching was after the issues started, otherwise I wouldn't have switched off and on.) So there might be a link between the new driver and my problems. I posted about it here:
https://www.mobileread.com/forums/sho...4789&page=4#57