My organization just switched to the Droid Razr Maxx, one of the phones is having an issue with adding a corporate sync email account. Whenever we try to add the account it says that it can't add because of duplicate account "Null". I don't see this "Null" account anywhere, so i can't seem to remove it. I'm not really sure what we can do, besides doing a reset and would only do that as a last course of action. We are running android version 4 and using office 365 exchange.
Try clearing Cache and Data for the following apps under
This should clear all the accounts (including the GMail one), and should allow you to add the Corporate account.