Missing shared mailbox

Question

I'm coming to this late, but hopefully I have enough details to get this out coherently...

We had a terminated user's mailbox setup as shared, and the on-prem AD account was accidentally deleted a few months. We recovered the account from the AD trash and (supposedly) the mailbox was recovered as well.

As of this week, the users that are still accessing the mailbox no longer see it though, and it's missing from the shared mailbox list. The user is still in AD on-prem and in the 365 portal this time; we're just missing the mailbox. I've done a check against soft-deleted mailboxes, and it's not there either. 

Any thoughts? I know we should use holds on cases like this...one thing at a time.

Answer 1

Hi Andy,

Thanks for the updates.

Since you can find some items in the mailbox, please try to recover it.

As you cannot find the mailbox in eDiscovery, it cannot be recovered. For your question "but I'm curious as to why there's such a clean break between the two mailboxes?", it is difficult to find the reason, thanks for your understanding.

Regards,

Robert

Answer 2

I made up the eDiscovery case and was able to locate 17584 items (~1.75GB) of data, but the results preview showed up as empty in the EAC. I attempted to export to PST, and it looks like the hold was able to recover the contents of her archive mailbox, but nothing in the main mailbox.

I'm guessing that means that the main mailbox was lost, but I'm curious as to why there's such a clean break between the two mailboxes?

Answer 3

I reapplied a license to the accoutn to generate mailbox, but it was empty. That would indicate the data was lost, correct?

Answer 4

Hi Andy,

Do you have any updates?

Regards,

Robert

Answer 5

Hi Andy,

Thanks for the updates.

Since the (shared) mailbox is originally created in Exchange Online, if the AD account of the mailbox gets deleted and then restored in AD, the AD account will be synced to Office 365 again, but the mailbox will go into the 30-day grace period since it is converted to a shared mailbox and has no Exchange Online license.

Given the situation, please assign an Exchange Online license to the user, then give full access to one user to see if the mailbox is still there. If not, I'm afraid the mailbox is permanently deleted and cannot be recovered.

Regards,

Robert