Created attachment 59514 [details] Logfile generated on failed start An segmentation fault does happen on startx. http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=667459
Can you bisect? A gdb backtrace would be nice.
Any reason why you are using UMS rather than KMS? Do you still have the problem with KMS? UMS is pretty much deprecated at this point.
I did deactivate KMS in 2010, presumably due to an error message regarding KMS. The problem vanished after activating KMS.
Mass closure: This bug has been untouched for more than six years, and is not obviously still valid. Please reopen this bug or file a new report if you continue to experience issues with current releases.
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