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Title
How to force the creation of a mailbox by the DSA (Directory Synchronisation Agent) -
Description
If all of the following conditions are true, newly migrated target users will not be mailbox enabled by the DSA (Directory Synchronisation Agent) until a full resync is performed.
1) Synchronisation is configured and "Specify Exchange options" tab of synchronisation properties is filled correctly to create a mailbox for target users
2) Corresponding source user has a mailbox
3) Synchronisation is not allowed to create users, only merge them
4) Migration session is used to create user in the target domain
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Cause
Delta sync will not create mailboxes for such users, because they have been worked on by a migration session and are regarded as synchronised. A modification of the source object is required to trigger a new cycle of synchronisation.However, modifying generic attributes, such as description will cause the delta sync to copy only the changed attribute to the target domain, without creating a mailbox.Only changing of msExchMailboxSecurityDescriptor, will force the delta synchronisation to mailbox-enable the target user. -
Resolution
There are two options available:
- Change permissions on the source mailbox rights, for example add QMM service account to have any rights on the source mailbox. Which user is added and what rights are provided does not matter, as long as msExchMailboxSecurityDescriptor attribute is modified. This can be achieved by utilising Add-MailboxPermission powershell cmd-let and useful for bulk modifications.
- If there are too many users affected rather than few - perform a full resync instead. Full resynchronisation will force creation of mailbox for all the users within the scope of the synchronisation.