Copy your Microsoft 365 mailboxes from tenant to tenant with ShareGate's Copy mailboxes feature, available with ShareGate Migrate Pro and Migrate Enterprise.
To learn how to upgrade your ShareGate license, see Upgrade or renew your subscription.
Note: Copy mailboxes comes with a few restrictions; we recommend reading the Copy mailboxes - Limitations article before running an Exchange Online migration.
Prerequisites
You have a Migrate Pro or Migrate Enterprise subscription.
You have global admin or Exchange admin permissions in your Microsoft 365 source and destination.
Your mailbox users have a valid Microsoft license and an email address assigned in the Microsoft Entra admin center.
Required Microsoft 365 permissions
A global admin must consent to a Microsoft 365 permission scope on your tenants once before using Copy mailboxes.
Consent can be granted when a global admin connects to their tenant while using Copy mailboxes, or it can be granted beforehand to allow an Exchange admin to perform migration.
To learn about the required permissions for mailbox migrations, see Microsoft 365 permission scopes required for ShareGate.
To learn how a global admin can grant consent to these permissions, see How a global or privileged role admin can consent to ShareGate's Microsoft 365 permission scopes.
How-to
Select Copy from the sidebar.
Select the Copy mailboxes tab.
Click Copy mailboxes.
Click the tenant selection box. It will display No connections if no tenants are connected to Copy mailboxes.
Select your source tenant or click + Add connection to add a new tenant.
If this is the first time connecting to the tenant with a mailbox migration feature, you will get prompted to consent to a Microsoft 365 permission scope as described in the Permissions consent section above.
You can click the refresh icon to update your users.
Place a check mark next to each mailbox you want to migrate.
You can use the search bar to find specific mailboxes.
Click on the Filter by icon in the Mailbox type column header to filter by User or Shared mailboxes.
You can select all your listed mailboxes with the check box in the Mailbox column header.
Click Continue to select destination.
Select your destination tenant or connect to a new one. The same conditions as step (5) apply.
You can only copy mailboxes to another tenant.
Click Continue to mailbox mapping.
Click Continue to recipient mapping.
Click Continue to copy summary.
Review the summary of your operation.
You can click Export list under Selected mailboxes to export a CSV of all the mailboxes you are copying.
If you get a warning about problematic on-hold destination mailboxes, you can click Export list of on-hold mailboxes to export a CSV report of the problematic mailboxes and see the article Detect and fix mailbox migration issues with hold and retention policy settings for a solution.
If you want to change your copy options and mappings, use the breadcrumb at the top to return to them. You will have to re-select all your options from the point you select.
Click Start copy or Save for later if you want to keep your migration parameters for another time.
With Save for later, you are prompted to resume your saved session the next time you launch Copy mailboxes. At that point, you can only continue from a saved session or discard it to start a different migration.
When you start your migration, you are taken to the copy summary report, where you can monitor your operation's progress.
Click Export report to download a detailed report of the copy operations to your drive. You can always retrieve your summary and detailed report from Tasks in ShareGate Migrate.
Detailed copy report
The detailed report provides valuable information about your migration operation. It allows you to review any warnings or errors that may have occurred, so you can resolve these issues for your users.
The copy report is exported as a zip file (.zip) and contains:
A summary file - This CSV file includes key details about the migration operation, including the start and end times, user names, source and destination email addresses, statuses of each mailbox copied, warnings, errors, and links to individual mailbox reports. The summary is named 01-Summary - task name.csv.
Individual reports for each mailbox included in the copy operation - Each mailbox report is named source_user_email_address.csv. In cases where there is a multi-session migration, the individual reports are organized in a separate folder for each session. Reports with more than 500,000 rows are split into multiple files.
To review errors and warnings, you can filter the Status column or your mailbox report in Excel to focus on these items. You can then look at the Details, Errors, and Warnings columns for details about what happened.
Incremental copy
You can use incremental copy for mailboxes previously migrated with ShareGate Migrate.
For more information, see Copy mailboxes - Incremental.
Tip: If you run into any problems during your initial migration, running an incremental migration is the first thing we recommend attempting to solve these issues.