AD Attributes that are changed when a mailbox moves to Office 365

There’s not a lot of great documentation available on what values change when an on-prem mailbox moves to the cloud.   The full list is below, but it’s important to note the following values since they are most often missed \ overlooked.


msExchRemoteRecipientType, previously null, will be set to 4


msExchRecipientTypeDetails gets changed from 1 to 2147483648


msExchRecipientDisplayType gets changed from 6 to -2147483642


Other values that change : legacyExchangeDN, homeMDB, homeMTA, homeServerName, ProxyAddresses, TargetAdddress

Reader Comments

  1. The values will change once the move is completed and Exchange on-prem changes the object type from UserMailbox to remote-UserMailbox. If you use "suspend when ready" for the MRS move, the values will NOT change until the move is finalized. For a new user,
    when you create their AD account and then use enable-remotemailbox or new-remotemailbox, Exchange onprem will set these values, however the msExchRemoteRecipientType value will be different, see my post from today about the msExchRemoteRecipientType attribute

  2. Hi When we perform move mailbox.. will it update FirstSynctime for active sync users. Does it has any relation with this parameter while moving mailbox. (local move)

  3. my customer’s attribute’s keep switching to Higher numbers on the MSExchRemoteRecipientType in the Azure AD logs ? what can be causing this to flip from 1 to 4 or 2 to 4 ? No Move requests for the users but yes there are pending Move requests for other users.

  4. homeMDB is blank for o365 users right? If we put a custom attribute in there (we have admin processes that use this) would that cause any problems?

    1. For a migrated mailbox, homeMDB is cleared via the MRS move, and for new-remoteMailbox, no homeMDB is created. If you populate that value, AAD Connect will push it to Azure, however it will be ignored. That said, it’s not supported to manually populate that attribute, you should avoid doing so.

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