Note: PowerShell integration requires a ShareGate Migrate Pro or Enterprise subscription. It is not available on the Essentials plan.
Copy your Microsoft 365 mailboxes between tenants or within the same 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.
SMTP is enabled for the source mailbox.
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.
Copy your mailboxes
Select Copy from the sidebar.
Select the Copy mailboxes tab, then click Copy mailboxes.
Connect your source and destination tenants. The first time you connect a tenant with a mailbox migration feature, you're asked to consent to a Microsoft 365 permission scope.
You can copy mailboxes to a different tenant or within the same tenant. When copying within the same tenant, auto-mapping is disabled by default, recipient mapping is skipped, and mapping a mailbox to itself is blocked.
Confirm the mailbox mapping and select the mailboxes to migrate.
ShareGate automatically maps your source mailboxes to matching destination mailboxes. You can review and modify these mappings.
Select the Warnings tab to review unmapped mailboxes.
If Microsoft Entra ID migration has already run between the same source and destination tenants, the mapping is pre-filled for you.
Use the search bar to find specific mailboxes, or filter by mailbox type with the Filter by icon in the Mailbox type column header.
When you use the select all checkbox at the top of the list, only mapped mailboxes are selected.
Click Continue to copy options.
If ShareGate detects unmapped recipients, a recipient mapping step appears next, showing only the unmapped recipients. If your mapping is already complete, this step is skipped.
Click Review.
Review the summary of your operation.
Click Export list under the number of mailboxes selected from everything when you expand it to export a CSV of the mailboxes you're copying.
If you get a warning about problematic on-hold destination mailboxes, click Export list of on-hold mailboxes to export a CSV report, then see Detect and fix mailbox migration issues with hold and retention policy settings for a solution.
To change your copy options or mapping, use the breadcrumb at the top. You'll need to re-select your options from that point onward.
Click Start copy or Save for later to keep your migration parameters for later.
With Save for later, you're prompted to resume your saved session the next time you launch Copy mailboxes. At that point, you can only continue from the saved session or discard it to start a different migration.
ShareGate takes you to the copy summary report, where you can track your migration'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 lets you review any warnings or errors that may have occurred so that you can resolve them 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 multi-session migrations, 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.
Note: The Message ID column shows the item's internal Exchange ID at the source, not the SMTP Message-ID found in email headers. This internal ID changes when an item is copied to a new mailbox, so the source and destination IDs will differ. The latter destination ID is shown in the separate Destination ID column.
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, we recommend starting with an incremental migration to resolve these issues.