The other day I was using a full licensed version Adobe Acrobat X as part of the CS6 suite and it suddenly stopped working. The only solution that I found was to reinstall which was a pain. It happened again and I found another solution recently. The following solution is a lot easier to use but still a pain.

1. Make sure you are connected to the internet.
2. Launch a regular CS6 product other than Acrobat or Flash Builder (for example: Photoshop, After Effects, Premier Pro, InDesign, Flash Professional, Illustrator, Dreamweaver.)
3. Click on Help->Deactivate .