I had a similar problem too. I was trying to browse to another users home folder to check disk usage. I launched a root nautilus through gksu nautilus. When I right clicked on the folder (in this case 'pictures') and selected properties I got the crash. Aport pointed me to this bug rather than reporting a new one, so I'm adding a little bit more information.
Firstly, the user in question is just a simple ASCII name ('betty') rather than from the extended character set (but, of course, it may not matter which part of the character set the characters come from). The dialogue as reported in the original bug appeared, but I wasn't trying to change the user and as I was running from a terminal it reported the following: ERROR:nautilus-properties-window.c:1836:schedule_owner_change_timeout: assertion failed: (NAUTILUS_IS_FILE (file)) -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1106283 Title: [13.04]nautilus crashed with SIGABRT in g_assertion_message() when trying to open file/folder's property dialog as root where file/folder belongs to user with Unicode CJK name. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/nautilus/+bug/1106283/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs