Comment # 4 on bug 1229803 from Stefan Hundhammer

Maybe simply start with the common approach for this kind of problem: Move that
user account's home directory away, and create a new, completely empty one:

root@mymachine> mv /home/user1 /home/user1.old
root@mymachine> mkdir /home/user1

...and then try again. If that works (which is very likely), check if any files
or subdirectories in the old home directory are owned by root, or if your
normal user account doesn't have permissions.

If that doesn't help, clear the newly created home directory and recursively
copy back the original one. Make sure that all files are owned by that user.

Then try removing config files and directories one by one until it starts
working.

But as Andreas wrote, this is a support case, not at all a bug of the
distribution. If this were a common problem, we'd see hundreds of complaints,
not only this one.