Fairly often, my Mac OS X 10.8 Mountain Lion “Messages” app shows the wrong number of unread messages.
Sometimes I can make the badge update after double-clicking every contact in my buddy list. With a big list, that is not a practical solution.
Instead, I’ve found that these steps seem to work:
- Quit the problem app
- Open Applications/Utilities/Terminal and run the following command:
- Launch the problem app