I have a question to uninstall an on premises Exchange 2010 completely after everything was moved to Office 365. The Migration to Office 365 was realized with hybrid Exchange.
The hybrid Exchange configuration is already disabled/uninstalled. The Azure AD Sync is still active.
Now we are at the point to remove the last Arbitration Mailbox with the following command:
" Get-Mailbox -Arbitration -Database "DB-Name" | Remove-Mailbox -Arbitration -RemoveLastArbitrationMailboxAllowed "
... and we receive the following error:
Can't remove the arbitration mailbox <mailbox-name> because it's being used for the approval workflow for existing recipients that have either membership restrictions or moderation enabled. You should either disable the approval features on those recipients or specify a different arbitration mailbox for those recipients before removing this arbitration mailbox
When I check which mailboxes are still using this arbitratoin Mailbox I get a list with all mailuser, mailcontacts, mailuniversaldistributiongroups and mailuniversalsecuritygroups (all these users are still migrated to O365).
What can I do now in the correct way to go on with my uninstalling of Exchange.
Would it be Ok when I do one of the both possible steps?:
1. Disable the arbitration Mailbox: "Get-Mailbox –Arbitration | Disable-Mailbox –Arbitration –DisableLastArbitrationMailboxAllowed"
2. Disabling the Moderation for all recipient: " Set-Mailbox "Mailbox-Name" -ModerationEanbled $false
Will I have a bad Impact with my Azure AD Sync and then to my Office 365 environment when I would realize one of the following steps?
Thanks for your reply