14.04 black screen from Unity, global menu, System Settings

[shochatd]

I have just upgraded a 32-bit system from 13.10 to 14.04. Several things cause me to get a black screen (top indicator area still showing). I can usually recover by waiting and clicking randomly on the black screen:
1. If I move my cursor to the left side to expose the Unity launcher, I get a black screen.
2. If I try to invoke the global menu for an application like Firefox or Terminal that uses it, I get a black screen and the global menu is inoperative (also, I thought there wasn't supposed to be a global menu in this release, but there seems to be -- but it doesn't work).
3. If I try to launch System Settings, I again get the black screen.
Any help would be much appreciated.

[kostkon]

You could try resetting your unity/compiz (http://www.webupd8.org/2012/10/how-to-reset-compiz-and-unity-in-ubuntu.html).

[shochatd]

Thanks for your response. I may try that (although that would mean I'd have to go back and turn off the jumping to full screen behavior etc.). For now, I've found a solution to the worst of it (the inoperable menus) by going into System Setting->Appearance->Behavior->Show menus "in the window's title bar". Those menus are fully functional (and I never liked the global menu anyway). The screen still goes black when I go into the Unity Launcher, but that is only temporary.

[shochatd]

I did the unity-reset and that seems to have eliminated the black screen. Thanks again. It did initially freeze my UI, so I ssh'd from another computer and killed gnome-session. Once I logged back in, all was well, and the global menu worked again. I did subsequently opt for menus in windows anyway and used ccsm to get smaller launcher icons and turn off grid. The latter gave me another freeze, which I cured the same way.