After the update from 11.04 to 11.10: when I shut down the pc sometimes it goes back to the login screen and then I have to do shutdown there which works well then.
Sometimes the pc shuts down but ends with the ubuntu splash screen and gets stuck there.
The issue may be driver related: I use the AMD/ATI FGLRX graphics driver.
I have a second pc where I also did the update to 11.10 and there I have no problem at all but I don't use the above driver but the NVIDIA graphics driver.
Both pc's have Ubuntu 11.10 64-bit.