Ok, solution was to delete everything from: ~/.thumbnails ~/.cache/thumbnails
After the reboot thumbnails were present in thunar and ristretto. Also the problem with the desktop wallpaper changer seemed to be working too. ** Changed in: xfdesktop4 (Ubuntu) Status: New => Fix Released -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1768361 Title: Can't select new wallpaer from alternative directory To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/xfdesktop4/+bug/1768361/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs