I've seen this bug a number of times on several installations, but as yet I'm not sure how to reproduce it. Basically the System Settings item on the "gear" menu stops working. It's not grayed out or anything. It just ignores my click or Enter key. Any clue how to work around this, like how to launch it from the command line or how to actually fix this problem?
I had the same issue so i tried this and work: open the terminal an insert: unity-control-center
this will open the default ubuntu control center if it is intalled, if not i will give you the instructions to install it, just follow them and the system settings will appear after this