Here is the situation:
- We are doing a project to migrate Exchange 2010 to Office 365 using hybrid migration.
- The company already has several existing Office 365 Business Premium licenses assigned to the users. These users already have an O365 mailbox, which got created as part of the Business Premium license but they aren't using these mailboxes.
- All users will get E1 license for email.
- We have got hybrid migration all setup. Users who never had an O365 mailbox have all managed to complete the sync process under migration batch.
- For users who already have an O365 mailbox, it isn't possible to choose these users under migration.
- We tried to remove Business Premium license for users who currently have one assigned, doing so removes the O365 mailboxes and we were able to start the migrate batch for these users.
- However, upon turning on E1 license for users who used to have Business Premium, their old empty O365 mailboxes came back alive and their migration batches all got corrupted.
- We tried to turn off E1 licenses for these problematic users but the mailboxes are still there (under EAC > recipients > mailboxes).
So the question is, what can we do to sync the mailboxes for these users who already had Business Premium? Removing the license from them doesn't help. Can we totally purge the O365 mailbox for these users?
Any help would be much appreciated.