Various icons from launcher are missing. The first one is from Home folder menu the second from Terminal the last one from Desktop Switcher. This happened after I upgraded to 11.10 from 11.04. I have created a New (Untitled Folder) folder in my desktop and the icon is missing too. The same occurs in System Settings menu too. Some icons like Appearance, Keyboard Layout are missing too. Sorry but I can't post a screenshot due to my reputation.
Any suggestions?
This can happen if you used a different Icon theme before upgrading for example Faenza Icon Theme.
To revert to one of the original Ubuntu-mono Icon themes, you need to install gnome-tweak-tool to do it in a simple way. After installation start the tool go to Theme, and change the Icon setting from the dropdown menu back to the original theme ubuntu-mono-light/dark. In case you want to have back the old theme reinstall it as you did the first time you used it.
Elaborating what was said in above answers. What worked for me was that I had used MyUnity to tweak the GUI, namely the "theme" section for "icons", setting this back to default (several worked actually) fixed the problem for me.
Try:
sudo unity --distro
that bug made me crazy, too!
If it didn't resolve, I remember that I deleted some .configuration file (you can see them in the /home, just press Ctrl+H), but now I didn't remember the name of the correct one. unity -h let you see some different options.
