Comment 5 for bug 1155687

I just upgraded from 12.10 to 13.04 release (about a month after release, still not fixed), and got this problem - after reboot and login the desktop never showed up, and there was an xmessage process with the message "Could not start d-bus. Can you call qdbus?" (the message actually did not appear on the screen, but I saw it in the htop full process list - it must have been displayed somewhere off-screen).

The fix is to run "apt-get install qdbus" and reboot (to reach the terminal for running this command, try ctrl-alt-F1).

Seems like quite a serious bug to me, performing a successful (so it seems) upgrade and ending up with an unusable system. Newbies would probably not even know how to reach the terminal without a desktop, and may not see the message with a clue as to what might be wrong.