(Modified 2011 Dec 18)
Xfce4 desktop corruption
I ran into a problem where, when I logged in, all windows would pop up at the top of the screen, with no title bars, and I couldn't move them or type in them. I found the fix on XFCE.org. The solution was simply to rename (or delete) ~/.cache/sessions/
I don't understand quite what was going on, but the window manager, xfwm4, wasn't running. In principle, I could have started xfwm4 from the corrupted desktop, but I couldn't type in any windows. So I had to move the above directory from a non-X terminal (e.g., CTRL-ALT-F2). More info at XFCE.org.
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