MikeyCPA:

That's an odd one. I'd check, 1) that your Windows System date has not been set back accidentally (I've seen users use the system date as a calendar to check a date and not understand that they are actually changing their system clock and that can cause all sorts of havoc) 2) Make sure no one has changed your Aging Periods under Settings, General Settings.

Other than that, I'd have to put some eyes on it and take a look remotely.