System mailbox corrupted

Question

We're migrating from exchange 2013 to 2019 on-prem.

All the mailboxes have been migrated to the new server including all the "system" mailbox as arbitration, auditing, etc

Checking the enviroment, before decomissioning the exchange 2013 server we noticed an error

we got this system mailbox that we don't understand what it is 

Get-Mailbox -filter { (name -like "SystemMailBox*") } | ft -AutoSize

WARNING: The object XXXXXX/Microsoft Exchange System Objects/SystemMailbox{3654B126-D8E0-47B3-85FA-2CA0FCFF7711} has been corrupted or isn't compatible with Microsoft support requirements, and it's in an inconsistent state. The following validation errors happened: WARNING: Database is mandatory on UserMailbox. WARNING: Database is mandatory on UserMailbox. Name                                                Alias                                               ServerName ProhibitSendQuota ----                                                -----                                               ---------- ----------------- SystemMailbox{3654B126-D8E0-47B3-85FA-2CA0FCFF7711} SystemMailbox{3654B126-D8E0-47B3-85FA-2CA0FCFF7711} XXXXXX   Unlimited

The server mentioned in the "servername" column, here changed to XXXXX, does not exists anymore as it was an old DC decomissioned.

The recipientTypeDetails of this mailbox is 

RecipientTypeDetails                   : LegacyMailbox

 

is it a mailbox that is needed, and so be recovered in a way, or can this be deleted ?

Answer 1

The only "system" mailboxes like that you need to worry about are the arbitration and auditlog mailboxes

Any others called called "system mailboxes" are usually tied to databases or servers and can left behind and ignored.

If you have moved all the arbitration mailboxes and auditlog mbx, you are good. Specifically the ones found with:

Get-Mailbox -Arbitration 
Get-Mailbox -AuditLog

https://www.alitajran.com/move-arbitration-mailboxes-in-exchange-server/

Answer 2

Hi,@Jimhex2024

Thanks for posting your question in the Microsoft Q&A forum.

Andy's answer is excellent, here are my additions.

I didn't find the arbitration mailbox you're talking about in Exchange 2016 CU8 or later, maybe it's too old, maybe not even from 2013. This arbitration mailbox is not required.

https://learn.microsoft.com/en-us/exchange/architecture/mailbox-servers/recreate-arbitration-mailboxes?view=exchserver-2019

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Answer 3

This mailbox could be tied to some older system functions that are no longer relevant to your current setup.

Just to clarify, have you already moved all the arbitration and auditlog mailboxes to the new server? Those are the critical ones to keep an eye on when migrating. If you’ve taken care of those, you’re probably good to go.

The corrupted mailbox you’re seeing might just be a leftover from the 2013 environment that’s no longer needed. Have you tried checking the mailbox properties or maybe running a test move to see if it’s still involved in anything active? If it's not being used and just causing issues, you should be able to safely remove it.

Also, did you happen to check if this mailbox has any legacy roles attached to it? Sometimes these old system mailboxes pop up after migrations, but aren’t really doing anything anymore. If it’s not tied to any important function, you could probably delete it.

Answer 4

This mailbox could be tied to some older system functions that are no longer relevant to your current setup.

Just to clarify, have you already moved all the arbitration and auditlog mailboxes to the new server? Those are the critical ones to keep an eye on when migrating. If you’ve taken care of those, you’re probably good to go.

The corrupted mailbox you’re seeing might just be a leftover from the 2013 environment that’s no longer needed. Have you tried checking the mailbox properties or maybe running a test move to see if it’s still involved in anything active? If it's not being used and just causing issues, you should be able to safely remove it.

Also, did you happen to check if this mailbox has any legacy roles attached to it? Sometimes these old system mailboxes pop up after migrations, but aren’t really doing anything anymore. If it’s not tied to any important function, you could probably delete it.