Installing Exchange 2010 Service Pack 1 Fails At Mailbox Role: Database is mandatory on UserMailbox.

In a recent incident, an Exchange server had a complete volume failure during testing. Exchange 2010 was reinstalled but when installing Service Pack 1, it failed upgrading the Mailbox Role. Upon reviewing the log, I found the following line:

Database is mandatory on UserMailbox. Property Name: Database

The error doesn’t explain the problem very well but it is basically saying that there is a UserMailbox without a database, which should never happen. The failure of the volume and subsequent reinstall of 2010 left the arbitration mailboxes (and one or two user mailboxes) orphaned. Most of the suggestions to resolve this problem list doing things like deleting the system mailboxes and running “ /PrepareAD”. After looking around, I was able to parse together a few other options and find a fix.

First, do a search in AD for the System mailboxes and make sure they exist in AD. (If they do not exist, check out this blog.)The three mailboxes are:

  • Discovery – SystemMailbox{e0dc1c29-89c3-4034-b678-e6c29d823ed9}
  • Message Approval – SystemMailbox{1f05a927-xxxx-xxxx-xxxx-xxxxxxxxxxxx} (where x is a random number)
  • Federated E-mail – FederatedEmail.4c1f4d8b-8179-4148-93bf-00a95fa1e042

Next, check out the status of their mailboxes:

Get-Mailbox –Arbitration

For this client, their Discovery and Message Approval mailboxes spat out error messages:

WARNING: The object XXXXXXXX.XXXXX/Users/SystemMailbox{e0dc1c29-89c3-4034-b678-e6c29d823ed9} 
has been corrupted, and it's in an inconsistent state. The following validation errors happened:
WARNING: Database is mandatory on UserMailbox.

The fix is a lovely, one-line powershell. It won’t do anything without prompting you first. To verify it fixes the issue after you run it, take the first half of the command (get-mailbox -arbitration) and run that again to confirm they are online and okay.

Get-Mailbox -Arbitration | Set-Mailbox -Arbitration –Database "Mailbox Database XXX"

Hopefully this saves somebody from causing a bigger mess than necessary. After running this, I was able to install Service Pack 1 just fine. YMMV.

Edit: I found the DiscoverySearchMailbox{D919BA05-46A6-415f-80AD-7E09334BB852} was orphaned as well. To fix this mailbox, I just ran the following PoSH.

Get-Mailbox -Identity "DiscoverySearchMailbox{D919BA05-46A6-415f-80AD-7E09334BB852}" | Set-Mailbox –Database "Mailbox Database XXX"


  1. Intense problem, but great work on that solution! Beware of SP1 RU4, it just got recalled in favor of a fix with RU5

  2. For ME the issues that you must consider once you want to upgrade to any SP’s for exchange 2010.
    1- extract 2010 SP2 to use as run setup /PrepareSchema, /PrepareAD etc…, also my exchange server 2010 all of it was crashed and the AD was missed everything, however i tried to to get
    back to the same AD , they said use another , but after my own conclusion, you only need
    to returen the commands for the exchange on the active directory but be aware first which the latest sp you have SP1, SP2 . and use the setup file for the one you already have.

    Also i got error about things for federation could not found as some of members said , or Display R5 from R4, and that some mailbox once you recieved the mailbox role.

    Ok so what i want to say is as follow:
    1- First if your EX server was smashed crashed what ever happy, just get the database
    and what you need.

    2- you dont have to create another new DC with new AD , you just need to do the following.
    – Delete the mailbox all federation, displaysearch , both systemmailbox.
    – then run the from the setup files the same verion you have. so
    * if you have the first version of EX , use the same file, iso, dvd what ever.
    * if you have already ex with SP1 use the extracted files setup from SP1 to run the
    common commands, setup /prepareAD /organizationName:your netbios name
    * if you want to upgrade from SP1 to SP2 , just get the extracted files from SP2
    and run the commands as follow and as i mension exactly.
    – Setup /PrepareLegacyExchangePermission
    will prepare exchange for SP2 installation.
    will Prepare permission, values.
    – Setup /PrepareSchema
    – Setup /PrepareAD /OrganizationName: your domain name “netbios Name”.
    this will prepare for you the Organization in the domain controller and if you have
    any missing object there will be recreated such the mailboxes that you delete in
    above steps. “federation, sysmailbox , displaysearchmailbox “.

    Finally , from my little experiance is to install the fresh DVD from microsoft then update ur
    EX with SP2.

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