I have recently moved a customer from his old Exchange 2007 enviroment to our Exchange 2010. His entire "Organization" consist of only 1 user.
When he attempts to update meetings that were scheduled on his Exchange 2007, he's getting error:
You don't have the permissions required to send messages from this mailbox.
I believe that this is due to the fact that the meetings have his old account listed there, so I tried to remove and add the new account and than send update, but still getting this error.
Which make me think that this error comes because Exchange is trying to send update to the deleted old user which no longer exists.
The question is, is there a way to remove the old user from the meetings without getting this error?