I work with multiple monitors (currently five) and occasionally the computer will go wonky and rearrange the monitors (usually due to a power glitch). When this happens, the start menu, Nexus, and Workshelf will go to random monitors or just crash. Finding them is a chore that could last for a while.

Last night was the latest glitch and I'm trying to recover from it. I found the start menu and Nexus but the workshelf is gone. It won't display its window when I select it from the start menu so I'm guessing it's crashing on startup. How can I get it to run?

Power glitches can cause all kinds of problems - that's why you should always have a voltage stabilised supply and a fast-reacting (a few microseconds) UPS.

That said, as regards the missing shelf, have you checked the Preferences (<Ctrl> + F11) -> Docks & Shelves panel to see if the shelf is perhaps set disabled?

Both the Nexus and Workshelf are enabled.

However...

The ctrl-F11 key brought up a window that showed me where each was located and allowed me to easily see what's running and change the location and dock position. My shelves are back to normal again! Thanks!

I put a sticky note on my computer to remind me of what key to press on the next glitch.