On Demand Migration - Mail Sync - New Feature Spotlight

Quest is excited to release a new mail sync feature within On Demand Migration that synchronizes mailbox changes from source to target.

This new feature allows migration operators to sync the full mailbox with every migration task to keep source and target synchronized.

  • Replicates content changes, moves, and deletions from source to target during each migration task
  • Removes the need to filter contents by date during initial migration tasks
  • Avoids creating duplicate contents in the target mailbox
  • Ensures migrated mailbox matches original mailbox to reduce user impact and keep users productive

What types of changes are synchronized?

On Demand Migration will synchronize the following changes for both the primary mailbox and the archive mailbox.


  • Updates message in target if changed in source, including changes to drafts
  • Moves message to different folder in target if moved in source
  • Deletes message in target if deleted in source

Folders and Subfolders

  • Updates folder and subfolder names in target if renamed in source
  • Moves folder to different location in target if moved in source
  • Deletes folder in target if deleted in source


  • Updates calendar entries in target if changed in source
  • Deletes calendar item in target if deleted in source

Note: For Contacts and Tasks - If these items are deleted in the source, they will not be deleted on the target.

What is an example mail sync scenario?

Let's imagine that a migration operator performs an initial mail migration task for the following mailbox. On Demand Migration will copy the mailbox contents from source to target.

Initial Migration Task

Source mailbox changes

After the initial mail migration, the user continues working out of their source mailbox. They receive new messages, they mark messages as read, they file messages into folders, they delete some messages, and they delete a personal folder.

Subsequent migration task, without Mail Sync (old behavior)

Without Mail Sync, when the migration operator submits another mail migration task for the mailbox, the task creates duplicate copies in the target mailbox for content that was moved or deleted in the source.  This duplication can result in possible mailbox quota issues in the target.

Subsequent migration task, with Mail Sync (new behavior)

With the new Mail Sync feature, the second migration task in this example will synchronize all source changes to the target without creating duplicates.

Why are we introducing this change?

When migrating a mailbox from one tenant to another, users expect their migrated mailbox to look the same as their original mailbox. Since users are constantly updating their active mailbox, this means that contents can change frequently in between migration tasks.

Without Mail Sync, users can end up with outdated and duplicated content in the target when multiple migrations are performed, requiring the users to perform post-migration review and cleanup.

How do I enable mail sync in my project?

You do not need to take any action to enable mail sync. Once mail sync is deployed to your On Demand region, all future mail migration tasks will automatically use the mail sync feature. Existing mail migration tasks will not be impacted and will complete their processing using the previous configuration.

Further information

For more information on this and many other features within On Demand Migration, check out the On Demand Migration User Guide or visit us at Quest.com. We welcome comments and questions, as your feedback helps to improve our products and make them work better for you. 

  • Great news and brings this in parity with legacy inter-forest migration scenarios where target messages are kept in sync and parity with the source data

  • It seems because of this new mail sync feature launch existing mail migration jobs are disturbed, re-running existing mail migration tasks copying all emails again to target mailbox & causing duplicates !! very much frustrating & annoying. We were on edge of scheduled cutover & everything got mashed. 

    I've already created a support case number 2099922 & requested an escalation, Here's case number & see if you can help here to resolve this to come out from this frustrating & erratic situation.

  • Hi Milan

    I wanted to reach out to you and let you know are working on your case and this issue with the upmost urgency, and have engaged the required people to resolve this issue as quickly as possible.


    Darin MacKenzie

  • If anyone else is experiencing this issue please contact our Technical Support team by creating a case here https://support.quest.com/create-service-request


    Darin MacKenzie

  • Assuming there is already content in the target mailbox, as the user is working in both source and target tenant - will the content be overwritten in the target?
    If yes, is there a possibility to opt-out from the sync-feature?

  • Hi Dominik, the mail sync feature will not modify or overwrite pre-existing content in the target mailbox. It only copies and modifies contents that originated from the source mailbox (it uses metadata to track which items are migrated from source). 

    Therefore, you can merge an active source mailbox with an active target mailbox, and the resulting target mailbox will have the combined contents.

  • Hi, how can i know if my tenant is already enabled for sync?
    Thanks, Elia
  • Hi Elia, Mail Sync is currently enabled for ODM projects in the AU, UK, and CA regions and is scheduled to be enabled in the EU and US regions next week. You can check the region for your OrgID by clicking the dropdown next to your email address in the upper right corner while logged into ODM.

    If you want to confirm the feature within your specific project, you can run a migration for one of your test mailboxes, then delete some items in the source mailbox, then run another migration, and then check whether the target items are deleted or duplicated. Alternately, you can submit a ticket to Support and ask them to check the Mail Sync status of your OrgID's region.

  • suppose if i just need to copy specific folder from source mailbox to target mailbox between two different tenant is that possible using on demand migration tool?