I don't know if I should dig up this old thread or not, but this issue is not solved on my computer.
I have re-installed a number of programs and the icon will be there for a while, then will revert to the generic icon. For example, I installed the latest version of iTunes on 10/4/13. The icon was fine for a couple of weeks, then reverted to the generic icon about 4 or 5 days ago. I installed the latest version of Adobe Reader on 10/18/13. The icon was fine until this morning.
This problem only occurs with certain programs: All MS Office programs, Apple programs (iTunes and Quicktime), and Intuit programs (Quickbooks and Turbotax). It doesn't happen with any other Microsoft products or any other programs.