Mission Control won't a launch (except via Launchpad)

Question

I updated this morning from SL to Mt Lion.  I wanted to set up Spaces (similar to what I had in SL) and I found that it's now done via Mission Control.  I've tried the various FKey ways (F3, F9) to launch Mission Control directly but the only way I could bring it up was to fire up Launchpad and then click the MC icon there -- or by assigning it to a hot-spot corner.
I've now set up my 8 Spaces so I guess I don't need to open Mission Control much and could probably live with bringing it up via Launchpad or the assigned hot spot.  But I'm curious about why it's not being invoked via the FKeys.  Any ideas?

Answer 1

Try deleting the com.apple.systempreferences.plist.
You need to look in your user Library/Preferences for the .plist. Either hold down the option key while using the Finder “Go To Folder” command and select your user Library in your home folder or use the Finder “Go To Folder” command and enter ~/Library/Preferences/com.apple.systempreferences.plist.  Move the .plist to your desktop.
Log out/in and test. If it works okay, delete the plist(s) from the desktop.
If the same, return the .plist(s) to where you got them from, overwriting the newer ones.
If you prefer to make your User library permanently visible, use the Terminal command found below.
Show User Library
You might want to bookmark the command. I had to use it again after I installed 10.8.4. I have also been informed that if you drag the user library to Finder it will remain visible.
If it soved the problem, you will probably have to reset some of your Preferences.