Some accounts already exist in target environment. The directory synchronization job creates new target disabled accounts and creates a linked mailbox. When merging with existing accounts, however, the mailbox type is a regular mailbox and not a linked mailbox. The DSA is working correctly; it can set the AEA properly and create a linked mailbox when it creates objects, but not when merging into existing objects.
Is it possible to disable all target accounts and to have linked mailboxes for every account in Exchange 2007/2010 environments?
Existing target accounts can be disabled, and the AEA can be set manually, via a script or another tool (Microsoft NOMAS tool, etc.). Once the AEA has been set, modify the value of the MsExchRecipientTypeDetails attribute to 2 and mailbox will appear as linked mailbox.
Additional Information:
msExchRecipientDisplayType and msExchRecipientTypeDetails - These two attributes are added to the Active Directory Schema during Exchange 2007/2010setup. They are used to determine the type of recipient in the Address Book, and are displayed in the Exchange Management Console under Recipient Configuration and in ADSI Edit.
msExchRecipientTypeDetails reflects whether it is a linked mailbox or not (note: this attribute is not always stamped with a value. Groups do not have this attribute set ). Here are some examples:
User Mailbox has the value 1
Linked Mailbox 2
Shared Mailbox 4
Legacy Mailbox 8
Room Mailbox 16
Equipment Mailbox 32
Mail Contact 64
Mail-enabled User 128
Mail-enabled Universal Distribution Group 256
Mail-enabled non-Universal Distribution Group 512
Mail-enabled Universal Security Group 1024
Dynamic Distribution Group 2048
Mail-enabled Public Folder 4096
System Attendant Mailbox 8192
Mailbox Database Mailbox 16384
Contact 131072
User 65536
Disabled User 2097152
msExchRecipientDisplayType is used by Microsoft to tag new group types like room mailboxes. Below is a list of the groups and their values:
Object Type Decimal Value
Universal Distribution Group 1
Universal Security Group 1073741833
Dynamic Distribution Group 3
Linked Mailbox, Shared Mailbox, or User Mailbox 1073741824
Room Mailbox 7
Equipment Mailbox 8
Mail User, Mail Contact 6
Public Folder 2
Also see the technet article: How to Convert a Mailbox to a Linked Mailbox
