How can I set msExchMailboxGUID attribute to null?
This can be set within Synchronization Rules Editor.
- This is not supported, if you have performed a directory synchronization using DirSync.
- It is supported, if performing a directory synchronization using AAD Sync, or AAD Connect.
- For more details on the correct order of steps to follow for directory synchronization, refer to KB004336.
Run the Synchronization Rules Editor as an administrator.
Click on In from AD – User Exchange to edit the Inbound Rule Type.
Select Transformations. Find the msExchMailboxGuid attribute.
Change it to the following:
Expression - msExchMailboxGuid - NULL - Checkmark Apply Once - Click on Update.
Enable AADSync or AAD Connect and perform a full synchronization.
Now users may be assigned an Exchange Online license, and MigrationWiz may be used to migrate their mailboxes to Office 365.