Exchange online shared mailboxes registration#
Exchange online shared mailboxes update#
So, update the user mailbox which should really be a shared mailbox, to match the values on the shared mailbox on the left. Check the attribute values which will probably be as below: AD Attribute value Then do the same with the incorrectly created mailbox which is showing on the mailboxes section of the EAC. Obviously this is unsupported so use at your own risk.įirst, make sure Advanced Features are enabled in ADUC, find a shared mailbox which has been created correctly, open it and open the attributes tab. This is pretty ridiculous, so fortunately there is an easy way of fixing it by modifying the AD attributes. The only supported Microsoft way to fix this is to migrate the mailbox back to on-prem, convert it to shared, and then migrate to Exchange Online again. There is no simple way to fix this error, since it the Exchange on-prem EAC has no way to convert from remote user to remote shared mailbox. I have seen this cause licensing and permissions errors. This causes a problem, because Exchange on-prem thinks that it is still a user mailbox, and it will be listed under mailboxes in the on-prem EAC, rather than under shared mailboxes, because the AD attributes have been set incorrectly.