Thread: Exchange calendar retention

I work for a government organization that has several hundred Android mobile devices syncing to exchange 2010. I have a particular user with a thunderbolt that is having some issues with his calendar. This user claims that all his appointments showed from previous months until recently. Now he says only the reoccurring appointments. Anything beyond the current month going back, will not show single one time appointments. I have been unable to find anything from google that states there is a maximum retention time for mail or calendar. Can anyone else here confirm whether they have old appointments, going back 1 to 2 months for single appointments. I have tried removing the exchange account from his phone, and deleted the mobile device in Outlook mobile devices as well with no change.