When you migrate mailboxes from one Exchange Server to another, there are minute chances of getting an error due to user misstep. The error can occur at any migration step, and in the present article, we will show you some common errors, and you can tackle them.

Here are a few of the most common error message you’re likely to encounter.

Error: Mailbox Database Mounting Failure
During message transition from one version of Exchange Server to another in a multiple domain environment, you may encounter complete failure during content replication with the following error –

Error Message: MapiExceptionNotFound: Unable to mount database (hr=0x8004010f, ec=-254678990)
What might be causing this Error? Quick Workaround
  • The root cause behind this error is the failure of mailbox database mounting during the attempt to replicate the content in public folders.
  • Basically this error is encountered in the Exchange management console when you try to create new mailbox DB in an environment with multiple domains and then try to mount the database.
  • If the migration operation fails, you can fix the problem by changing a few settings in the Exchange Management Shell as described in the below cmdlet – Set –ADServerSettings –PreferredServer
  • This command sets the preferred AD server in the Exchange Management Shell


Error: Connectivity Issues
Sometimes administrators will encounter network errors that interrupt the mailbox movement from one version to another even after you’ve completed the installation. In such a scenario, you must check whether your mailbox DB is mounted or not.

Error Message: MapiExceptionNetworkError: Unable to make admin interface connection to server.
What might be causing this Error? Quick Workaround
  • This error occurs when there are connectivity issues with the server, the Exchange is working properly but the server fails to send/receive messages.
  • This problem can be fixed by restarting the System Attendant Service. Once this is done, the system is rebooted and the DB is mounted, you will get rid of this issue.


Error: Failed Mailbox Move Requests
When the mailbox move request cannot be completed the migration may well fail. You might encounter errors during the attempt to serve a local move request while transitioning a user from one mailbox DB to another mailbox database. Subsequently the new user fails to communicate with the mailbox DB and is unable to send/receive emails since there is no access to “Outlook Web Access” due to failed login.

Error Messages:

  1. MapiExceptionLogonFailed: Unable to make connection to the server.
  2. MapiExceptionLogonFailed: Unable to open message store.
What might be causing this Error? Quick Workaround
  • Error (1) occurs when the local move request operation performed from Exchange Server 2010 fails due to the database being offline.
  • Error (2) occurs when the user fails to connect with the new mailbox database and hence cannot access mailboxes. This can happen due to the mailboxes are in the process of being transitioned, issues with mailbox replication service, proper admin rights and permissions are not granted to users etc.
  • Grant “full access permission” to the mailbox DB on relevant server to the Exchange Servers group by navigating to “Exchange System Manager, initiating a right click on the “Storage Group/Mailbox store and select the “Security” option from the dropdown menu. If you don’t see the Exchange Servers group on the window, you can add one here and then grant it the full permission access to resolve the issue.


Error: Mailbox Corruption Error
While performing a mailbox migration between two data stores or Exchange servers, a particular mailbox may exceed the maximum limit of the number of corrupted mailboxes that was assigned for a specific move request. As a result, the system returns a mailbox corruption error message.

Error Message: This mailbox exceeded the maximum number of corrupted items that were specified for this move request.
What might be causing this Error? Quick Workaround
  • Error occurs when the local move request operation performed from Exchange Server 2010 fails with database being offline.
  • The above mentioned problem of mailbox corruption can be resolved by changing some settings in the Exchange filters. To get around this you need to increase the limit of the number of corrupt emails that can be transitioned to the data stores by resetting the values in the Exchange filters. This limit can be reset in two ways – the first is with the usage of PowerShell wherein you can fix the problem by running the command described below –

    New-MoveRequest –identity username –TargetDatabase “database name” -MRSServer CASServer -BadItemLimit XXX

    In the above code, XXX represents the email count one needs to change. You can easily specify the limit of the number of emails to be migrated by incrementing this count according to your requirements. Also, in the field “database name”, you can specify the name of the particular database that possesses corrupt items.


While its common to experience mailbox migration errors half the battle is understanding what they actually mean. These steps should help you with workarounds however if the issue persists you may find it easier (and in the long run cheaper) to opt for a third party tool such as “Kernel Migrator for Exchange”. Kernel Migrator performs pre-migration analysis and offer detailed migration reports so you can identify such issues before you even start the migration. From Office 365 migration to Exchange migration and public folder migration to cross forest migration, Kernel Migrator for Exchange covers it all. It also provides advanced filtering, two-way synchronization, better co-existence features and the ability to schedule migration jobs as per the convenience of the IT administrator.