I just upgraded my desktop from Ubuntu 12.04 to 12.10. Everything looked good until I tried to launch an application – then Unity frooze. I thought it might be nvidia driver issues and tried:
apt-get remove nvidia-current; apt-get install nvidia-current-updates; reboot;
However, this didn’t fixed the problem. After some searching around it appears that reseting Unity to default fixed the issue. I wish the developers would make an upgrade script which checks that the Unity settings are okay (Firefox does this after an upgrade). Anyhow, here is how to reset Unity to its defaults. You can either:
unity --reset
Or you can use this script which manages the process for you: It is hosted on bitbucket at https://github.com/phanimahesh/unity-revamp . However, I installed it from the PPA:
sudo add-apt-repository ppa:amith/ubuntutools sudo apt-get update sudo apt-get install unity-reset unity-reset
I used the script and it worked really well. Hurray.