I have let it scan all night and the wheel is still spinning. Sometimes it doesn't say sorting it is just stuck with the spinning wheel.
Does this happen only with specific folders that you're browsing? Have you checked your disk with the Disk Utility application?
Another thing you can try is to reset your preferences. There is a thread in this message board (it's a sticky post at the top) that explains how to start over with your preferences. They're PM5-centric but most of the instructions still apply to PM 4.6.x.
If neither of these approaches fix your issue, then I suggest contacting our tech support folks via telephone and they'll troubleshoot the issue with you. +1 503-547-2888, M-F 9AM-5PM PST.
-Kirk