Roughly since end of May, i.e. since the installation of libX11-1.5.99.902 (now I have libX11-1.6.0) I have difficulties to login into a gnome-session on a system with a NVIDIA Quadro NVS 140M card. At two of three attempts I get "Oh No! Something has gone wrong." I get this message too, if I log off. Furthermore the desktop background is black inspite of its setting (which is a green gradien). I reported this issue also at Bug 471396. I have installed: x11-base/nouveau-drm-99999999 x11-drivers/xf86-video-nouveau-1.0.8 and CONFIG_DRM_NOUVEAU=y is set. Should I remove nouveau-drm? Reproducible: Always
Unfortunately, the "Oh no" message could mean almost anything, making it impossible to diagnose the issue. Could you please get a log of whatever it is that is crashing? For example, if the gnome-shell process is segfaulting, try rebuilding relevant packages with debug symbols and getting a backtrace using abrt.
Also test with 3.8 (this also reminds me another bug from you that this could be a duplicate of)
