"Bluetooth Not Available" on MacBook Pro Retina w/ Mac OS X Mountain Lion

Today I started my MacBook and my Apple Mouse did not work. When I clicked on the Bluetooth Icon it produced the following message: "Bluetooth Not Available" (MacBook Pro Retina w/ Mac OS X Mountain Lion).

I read that resetting the system management controller (SMC) might work - and it did! For my Intel-based Macbook the directions are as follows:

Note: Portable computers that have a battery you should not remove on your own include MacBook Pro (Early 2009) and later, all models of MacBook Air, and MacBook (Late 2009).
Shut down the computer.

1. Plug in the MagSafe power adapter to a power source, connecting it to the Mac if its not already connected.
2. On the built-in keyboard, press the (left side) Shift-Control-Option keys and the power button at the same time.
3. Release all the keys and the power button at the same time.
4. Press the power button to turn on the computer.

Note: The LED on the MagSafe power adapter may change states or temporarily turn off when you reset the SMC.

If you have a different MacBook, more information can be found here: http://support.apple.com/kb/ht3964