Installing kdebase-workspace-dbg didn't give me a better backtrace, unfortunately. From the .crash file: Stacktrace: #0 0xb7f7b430 in ?? () -- kwin crashed with SIGSEGV https://bugs.launchpad.net/bugs/282874 You received this bug notification because you are a member of Kubuntu Bugs, which is subscribed to kdebase-workspace in ubuntu.