It's not 100% clear to me in this report if it's kwin or plasmashell freezing.
If plasmashell, then this is possibly a dup of bug #341951 (and https://bugs.freedesktop.org/show_bug.cgi?id=84252 ) -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1440210 Title: KWin crashes multiple times a day and often has to be restarted manually. To manage notifications about this bug go to: https://bugs.launchpad.net/kdebase-workspace/+bug/1440210/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs