I ran LiveUpdate interactively, and it said there was a patch available, which I accepted. I'm on W7 with all patches and (now) on NIS 21.2.0.38.
When the patch process started running, the entire desktop behind the NIS patch window went blank except for the wallpaper. At first I thought, "Oh, it's just because the icons are changing and it's rebuilding the desktop".
However, when the patch was done, and I exited NIS, my desktop was still entirely blank except for the wallpaper: no icons, no notification area, no taskbar. There wasn't even a Windows START button! I clicked around the screen, especially where the Windows START button would be, but no go.
I didn't know if there was a keyboard shortcut for the windows START button, so I finally just powered off my machine, waited 30 seconds, and then started it up again. Eventually,...... everything came back onto the desktop after the start up.
But, frankly, I didn't need the stress.
I had already patched two other machines and didn't have this problem. But the one that did have the problem is the least-used of the 3 by far.