I've got the same problem, if I start some application e.g. Savage (game) there is following Error: xcb_xlib.c:50: xcb_xlib_unlock: Assertion `c->xlib.lock' failed.
I've found some other people in different german speaking forums which have the same problem e.g with OOo. If they install the the Package from http://packages.debian.org/unstable/libs/libx11-6 the problem is solved. I don't want to do that because I wan't a clean Feisty System. Some Specs about my computer: http://hwdb.ubuntu.com/?xml=b222c842601aa7b4bd65b0bf544733d1 AMD 3800+, Nvidia GF 6800GT (nvidia-glx from repo) Please ask if I can do something or you need more info. Thanks for your work! -- c->xlib.lock https://launchpad.net/bugs/87390 -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs