Manage Exchange Hybrid Migration

Managing Exchange Server migration within a hybrid environment

You are using an AD synchronization tool such as Azure Active Directory Connect or Azure AD Sync to sync the data within your hybrid Exchange environment and would like to configure certain attributes for performing on-premise migration.

Resolution:

For performing on-premise Exchange migration within your hybrid environment, you need to set the attribute msExchMailboxGuid to NULL. Follow the steps outlined below to configure the attribute status.

• Set the attribute msExchMailboxGuid to NULL
• Remove the attribute msExchMailboxGuid from the AD synchronization

Set the attribute msExchMailboxGuid to NULL

1. Use the following cmdlet to stop the scheduler in Azure AD Connect.

   Set-ADSyncScheduler -SyncCycleEnabled $false

2. Run the Synchronization Rules Editor tool from the Start menu as administrator as shown.

   

3. Select the option Inbound under Direction and choose the rule In from AD - User Exchange. Note down the Precedence value corresponding to this row and click on the Edit button below to edit the rule.
4. Click Yes to disable the rule and create a copy of the rule. Under Descriptions, change the value of the Precedence to 200.
5. In the Transformations tab look for the attribute msExchMailboxGuid and set the following values.
   • Under Flow Type->Select Expression
   • Under Source, corresponding to this row-> Select NULL
   • Select the checkbox Apply Once
   • Under Merge Type->Select Update.
   • Click Save after configuring the above changes and delete the rule that you disabled in Step 4.

   Change the Precedence value in this rule to the one you noted down under Step 3.

6. Use the following command to restart the scheduler you had turned off in Step 1.

   Set-ADSyncScheduler -SyncCycleEnabled $true

7. Use the following command to perform a full synchronization.

   Start-ADSyncSyncCycle -PolicyType Initial

   After performing the synchronization, you can perform migration within your hybrid environment by creating mailboxes and assigning licences to your Office 365 account.

Steps to delete users from Azure AD admin center

• Login to Azure AD admin center from this link.
• Select Users from the left pane and navigate to Deleted users.

  

• Select the users you want to delete and click the button Delete permanently to permanently delete all the users. Click Yes to confirm.

Configure AD Sync Tool to exclude the attribute msExchMailboxGuid from sync

You can prevent the attribute msExchMailboxGuid from syncing every time by following the steps below.

1. Open Azure AD Connect app.
2. Click on Configure and choose Custom synchronization options from the list. Click Next.
3. Enter your Azure credentials under Connect to Azure AD.
4. In the Domain / OU Filtering tab select the option HybridUsers and click on the Next button at the bottom.
5. In the Azure AD Attributes tab, uncheck the option msExchMailboxGuid and check the option I want to further limit the attributes exported to Azure AD and click on the Next button.
6. In the Configure tab, check mark the option Start the synchronization process when configuration completes.
7. Click on the Configure button to start the synchronization. After the synchronization is complete, the attribute msExchMailboxGuid is no longer synced to the user accounts.