Screensaver hot corner no longer working in 10.9.1

Question

Upgraded to 10.9.1 from 10.9
Moved my moise pointer into the hot corner to activate the screensaver and it did not work.
I tried:
A different screensaver.
Activating a different corner
Changing the option on the corner to "Mission Control" (which worked) then back to Activate ScreenSaver and it did not work.
Turning the corner to "-", setting it. Then going back in and setting it back to the screensaver. It did not work.

Answer 1

Back up all data.
Triple-click anywhere in the line below on this page to select it:
~/Library/Preferences/com.apple.dock.plist
Right-click or control-click the line and select
Services ▹ Reveal in Finder (or just Reveal)
from the contextual menu.* A folder should open with an item selected. Move the selected item to the Desktop, leaving the window open. Log out, log back in, and test. If there's no change, quit again and put the item you moved back where it was, overwriting the one that may have been created in its place. Otherwise, delete the item you moved. If possible, restore it from a backup that predates the problem.
*If you don't see the contextual menu item, copy the selected text to the Clipboard by pressing the key combination  command-C. In the Finder, select
Go ▹ Go to Folder...
from the menu bar, paste into the box that opens (command-V). You won't see what you pasted because a line break is included. Press return.