If you ever find yourself with a flashing unread PM icon that you can't get rid of try one of the following methods.
First, simply go to your Unread PMs Inbox. This page should resync your PM count and get rid of the flashing PM icon.
If that does not work then you are going to need to reset your personal folder count. Go to the Manage Personal Folders page and you should see the following:
Hit reset, as circled above, and your PM counts will be reset and you should no longer see the flashing unread PM icon.
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