I had installed Gnome Shell and LXDE along with KDE 4.9.5 in Mint 13 KDE (graphics card: Ati Radeon 4550 HD). I wanted to get rid of Gnome and LXDE and uninstalled major part of their files with apt remove, purge and autoremove (log here: http://pastebin.com/7NnefKNi ). Messed something up since now Kwin started to randomly crash at startup and plasma sometimes. too Error messages (partly translated):
Executed file: kwin processor identifier: 1862 Signal: Segmentation fault (11)
Executed file: kwin processor identifier: 4997 Signal: Segmentation fault (11)
Executed file: plasma-desktop processor identifier: 3394 Signal: Segmentation fault (11)

It halts kwin and turns compositing effects off. I can turn them on and restart Kwin with: kwin --replace and it usually works again. Sometimes startup goes without problems. Kwin, plasma and compositing works then normally or when I restart kwin.

What could I do? Tried to remove kwin config files. Seem to work first but then kwin began to crash again.

It's also Plasma crashing. I'd first go with

sudo apt-get install kubuntu-desktop

to ensure all required packages of kubuntu-desktop are present.

I installed kubuntu-desktop and it downloaded 30MB of programs and libraries. I rebooted few times and it still gives some times an error message about kwin crashing but it restarts it automatically so it's at least a bit better now.

it's an improvement, but KWin should not crash

When the next time the Crash Dialog appears, please click on developer information and create the backtrace and paste it here (or better on a paste). Normally we can see what is causing the problem from the backtrace.

Ok here is crash developer informaton:
http://pastebin.com/39pvuNMC

OK, known issue with the fglrx driver. Two possible solutions:
1. switch to the (for KWin better) free radeon driver
2. disable the blur effect and do not use the option "Scale Method" "Accurate" (any other value is fine) in the advanced desktop effect settings

Thanks, it seems to work. It's very interesting because that shouldn't have anything to do with removing GTK DEs. I've used this system half an year now with blurring and other effects on without problems. As I read APT history log more closely there's actually a little update I accidentally made during uninstallation process and didn't pay attention. It's most probably the reason why the driver started to misbehave.

Apt log:
Install: linux-headers-3.2.0-36:amd64 (3.2.0-36.57, automatic), linux-image-3.2.0-36-generic:amd64 (3.2.0-36.57), linux-headers-3.2.0-36-generic:amd64 (3.2.0-36.57, automatic)
Upgrade: xserver-xorg-video-all:amd64 (7.6+12ubuntu1, 7.6+12ubuntu2), linux-generic:amd64 (3.2.0.34.37, 3.2.0.36.43), xserver-xorg-input-all:amd64 (7.6+12ubuntu1, 7.6+12ubuntu2), linux-headers-generic:amd64 (3.2.0.34.37, 3.2.0.36.43), xserver-xorg:amd64 (7.6+12ubuntu1, 7.6+12ubuntu2), linux-image-generic:amd64 (3.2.0.34.37, 3.2.0.36.43), xorg:amd64 (7.6+12ubuntu1, 7.6+12ubuntu2), linux-libc-dev:amd64 (3.2.0-34.53, 3.2.0-36.57), mountall:amd64 (2.36, 2.36.3)

I downgraded xorg-packages but that didn't seem be enough to do the trick. Might it be usefull and safe to uninstall/downgrade those linux headers, kernel images etc?

I don't see the fglrx driver in that list. The updates seem all fine. Maybe you got accidentally transited to the fglrx driver.

mgraesslin wrote:I don't see the fglrx driver in that list. The updates seem all fine. Maybe you got accidentally transited to the fglrx driver.

Ok, dunno what caused this but luckily kwin doesn't crash anymore.