steveenmiller
New Member
When an organization is planning a Microsoft 365 tenant migration, mailboxes subject to litigation hold, retention policies, or an ongoing investigation require additional planning. These mailboxes may contain business records that must remain available for compliance or legal review, even while the company is consolidating its IT environment after an acquisition or restructuring.
The first step is to identify all affected accounts before scheduling migration batches. Administrators should work with the compliance team to confirm which mailboxes are subject to litigation hold, retention requirements, or eDiscovery cases. They should also determine whether the mailbox contains an online archive and whether there are any preservation requirements that extend beyond the primary mailbox.
A common mistake is to assume that moving mailbox messages automatically transfers the original tenant's compliance configuration. Retention policies, hold settings, eDiscovery cases, permissions, and audit requirements need to be assessed separately. A destination mailbox may contain the expected emails without inheriting the same preservation settings as the source.
Before proceeding, verify the migration method's support for held mailboxes and archived content. Some migration workflows have specific restrictions that may prevent certain mailbox types from being transferred directly. If a mailbox is on hold, do not remove the hold or decommission the source tenant simply to make the migration easier. Get approval from the appropriate legal and compliance stakeholders first.
The SysInfo Microsoft 365 Tenant to Tenant Migration Tool supports migration of primary and shared mailboxes, but its documented mailbox workflow does not support public folders, online archive mailboxes, or group mailboxes. Organizations with these requirements should plan a separate process and validate compatibility before starting the project.
I would recommend testing the migration process with a representative mailbox that has similar characteristics but is not subject to active legal restrictions. Confirm message counts, attachments, folder structures, and reports. For mailboxes under formal preservation requirements, have the compliance team approve the process and independently verify that the necessary records remain accessible.
Microsoft's tenant-to-tenant migration planning guidance is a useful reference for evaluating workload dependencies and migration prerequisites.
The key point is that a tenant migration and a compliance-preservation plan are related but separate tasks. Identifying held mailboxes early helps prevent last-minute delays and reduces the risk of disrupting access to records needed for legal or regulatory purposes.
The first step is to identify all affected accounts before scheduling migration batches. Administrators should work with the compliance team to confirm which mailboxes are subject to litigation hold, retention requirements, or eDiscovery cases. They should also determine whether the mailbox contains an online archive and whether there are any preservation requirements that extend beyond the primary mailbox.
A common mistake is to assume that moving mailbox messages automatically transfers the original tenant's compliance configuration. Retention policies, hold settings, eDiscovery cases, permissions, and audit requirements need to be assessed separately. A destination mailbox may contain the expected emails without inheriting the same preservation settings as the source.
Before proceeding, verify the migration method's support for held mailboxes and archived content. Some migration workflows have specific restrictions that may prevent certain mailbox types from being transferred directly. If a mailbox is on hold, do not remove the hold or decommission the source tenant simply to make the migration easier. Get approval from the appropriate legal and compliance stakeholders first.
The SysInfo Microsoft 365 Tenant to Tenant Migration Tool supports migration of primary and shared mailboxes, but its documented mailbox workflow does not support public folders, online archive mailboxes, or group mailboxes. Organizations with these requirements should plan a separate process and validate compatibility before starting the project.
I would recommend testing the migration process with a representative mailbox that has similar characteristics but is not subject to active legal restrictions. Confirm message counts, attachments, folder structures, and reports. For mailboxes under formal preservation requirements, have the compliance team approve the process and independently verify that the necessary records remain accessible.
Microsoft's tenant-to-tenant migration planning guidance is a useful reference for evaluating workload dependencies and migration prerequisites.
The key point is that a tenant migration and a compliance-preservation plan are related but separate tasks. Identifying held mailboxes early helps prevent last-minute delays and reduces the risk of disrupting access to records needed for legal or regulatory purposes.
