This bug has been reported on Ubuntu Launchpad as:
I've just upgraded Xubuntu 9.10 to 10.4 and tried to change the theme with the Settings Manager. I could easily change the themes several times but for the "Wildbush" theme the screen turned into black and I was throughn out to the login screen. I tried to log in several times but I couldn't. I got back the login screen every time.
At last I logged in with a different wm (fluxbox) and deleted the ~/.config/xfce4/xfconf/xfce-perchannel-xml directory. It helped me to log into XFCE again.
DistroRelease: Ubuntu 10.04
ProcVersionSignature: Ubuntu 2.6.32-21.32-generic 184.108.40.206+drm33.2
Uname: Linux 2.6.32-21-generic x86_64
This bug is reproducable with both 32bit and 64bit systems.
Couple of comments, if you are sent back to the login screen, it's not the WM crashing but the whole X session, meaning that it's most likely the gtk theme/engine causing the issue.
Anyway, when a process crashes, we need a backtrace of the process to investigate, there is not much I can do without a proper backtrace of the process.
In doubt, please ask the maintainers on Xfce in Ubuntu/Xubuntu to assist you in getting the backtrace and report back to us.
But such issues should be investigated at the distribution level first, and escalated to us upstream with all the required data.
... Or X itself, there was a bug in Xorg causing just that in some cases. Do you see X crashing in the Xorg logs (usually Xorg.0.log.old but that may differ on your distribution)
(In reply to comment #1)
> Couple of comments, if you are sent back to the login screen, it's not the WM
> crashing but the whole X session, meaning that it's most likely the gtk
> theme/engine causing the issue.
> Anyway, when a process crashes, we need a backtrace of the process to
> investigate, there is not much I can do without a proper backtrace of the
> In doubt, please ask the maintainers on Xfce in Ubuntu/Xubuntu to assist you in
> getting the backtrace and report back to us.
> But such issues should be investigated at the distribution level first, and
> escalated to us upstream with all the required data.
I have the same problem on a different Distribution (Slackware13.1) with the new XFCE4.8 pre2. So I think, it is not a problem with (X)Ubuntu.
Created attachment 3296
maybe this gives a hint?
Can I do anything else to help on this bug?
Yeap, thanks, it helps. The X server crashes with:
Fatal server error:
exaGetPixmapFirstPixel called for invalid bpp 1
That is a bug in the X server or the Xorg driver and definitely not an application issue, this should be reported and tracked with Xorg.
It is reported here https://bugs.freedesktop.org/show_bug.cgi?id=24703
Xorg devs are looking for a backtrace of the X server, from gdb.
http://lists.freedesktop.org/archives/xorg/2010-January/048821.html may also be of interest.
*** This bug has been marked as a duplicate of bug 5966 ***