After several months without problem, I just experienced this issue… and the two solutions given in Launchpad (
aptitude reinstall gnome-settings-daemon and
sleep 2) don’t help at all.
So, how to deal with that? Well, it’s simple: just open a terminal window and in it write:
Now the theme is restored, but the icons in the file manager still look bad. That’s because of Nautilus the file manager. You have to kill it. Yes, kill it:
$ killall nautilus
So Nautilus will be restarted after that, with the right icons. You can now close your terminal window and go back to a normal life.
I hope the Ubuntu people will fix this issue before the release of the next version, Natty Narwhal, which should be released this month.