Can't open mail preferences
My mail preferences suddenly decided they don't want me to make any changes anymore.
I just noticed tonight, but I haven't bothered with any prefs for some time. Probably a few months, so who knows. When I try to access preferences now, I get the little rainbow whirligig and mail is completely locked. I have to force quit Mail.
I can use Mail normally otherwise.
MacBook, OS X Mountain Lion (10.8.2)