Admins are unable to complete some cross-tenant mailbox migrations in Exchange Online

Title: Admins are unable to complete some cross-tenant mailbox migrations in Exchange Online User impact: Admins may have been unable to perform tenant to tenant migrations and offboarding moves in the Exchange admin center. More info: While we worked on developing a long-term solution, admins may have been able to use PowerShell for the affected migrations and moves with the following cmdlet against the affected mailboxes: Set-MoveRequest "user@yourdomain.com" -SkipMoving FolderRestrictions Next, the tenant admin could have resumed the move request using the cmdlet: Resume-MoveRequest "user@yourdomain.com" This would allow the affected move jobs to continue to make progress. Final status: We confirmed that the cross-tenant migration process has successfully completed for a subset of affected admins, validating that our configuration change has resolved the event. Scope of impact: Some admins attempting to perform tenant to tenant migrations and offboarding moves in the Exchange admin center may have been impacted. Start time: Saturday, February 14, 2026, at 12:48 AM UTC End time: Friday, August 14, 2026, at 5:24 PM UTC Root cause: A change introduced a code regression to Mailbox Replication Service (MRS) caused intermittent failures for tenant-to-tenant migration actions or offboarding moves as the property tags needed to complete the request were not being properly configured. Next steps: - We're reviewing the responsible change to better understand what led to the configuration error that resulted in impact and prevent similar future occurrences. This is the final update for the event.

Title: Admins are unable to complete some cross-tenant mailbox migrations in Exchange Online User impact: Admins may have been unable to perform tenant to tenant migrations and offboarding moves in the Exchange admin center. More info: While we worked on developing a long-term solution, admins may have been able to use PowerShell for the affected migrations and moves with the following cmdlet against the affected mailboxes: Set-MoveRequest "user@yourdomain.com" -SkipMoving FolderRestrictions Next, the tenant admin could have resumed the move request using the cmdlet: Resume-MoveRequest "user@yourdomain.com" This would allow the affected move jobs to continue to make progress. Final status: We confirmed that the cross-tenant migration process has successfully completed for a subset of affected admins, validating that our configuration change has resolved the event. Scope of impact: Some admins attempting to perform tenant to tenant migrations and offboarding moves in the Exchange admin center may have been impacted. Start time: Saturday, February 14, 2026, at 12:48 AM UTC End time: Friday, August 14, 2026, at 5:24 PM UTC Root cause: A change introduced a code regression to Mailbox Replication Service (MRS) caused intermittent failures for tenant-to-tenant migration actions or offboarding moves as the property tags needed to complete the request were not being properly configured. Next steps: - We're reviewing the responsible change to better understand what led to the configuration error that resulted in impact and prevent similar future occurrences. This is the final update for the event.

Title: Admins are unable to complete some cross-tenant mailbox migrations in Exchange Online User impact: Admins may be unable to perform tenant to tenant migrations and offboarding moves in the Exchange admin center. More info: While we work on developing a long-term solution, admins may be able to use PowerShell for the affected migrations and moves with the following cmdlet against the affected mailboxes: Set-MoveRequest "user@yourdomain.com" -SkipMoving FolderRestrictions Next, the tenant admin may have resume the move request using the cmdlet: Resume-MoveRequest "user@yourdomain.com" This would allow the affected move jobs to continue to make progress. Current status: We're coordinating with a subset of affected admins who are in the process of completing a cross-tenant mailbox migration to monitor progress, which will help us validate remediation for all impacted admins. Scope of impact: Some admins attempting to perform tenant to tenant migrations and offboarding moves in the Exchange admin center may be impacted. This information may be updated as our investigation continues. Start time: Saturday, February 14, 2026, at 12:48 AM UTC Root cause: A change introduced a code regression to Mailbox Replication Service (MRS), which is causing intermittent failures for tenant-to-tenant migration actions or offboarding moves as the property tags needed to complete the request are not being properly configured. Next update by: Monday, August 24, 2026, at 9:00 PM UTC

Title: Admins are unable to complete some cross-tenant mailbox migrations in Exchange Online User impact: Admins may be unable to perform tenant to tenant migrations and offboarding moves in the Exchange admin center. More info: While we work on developing a long-term solution, admins may be able to use PowerShell for the affected migrations and moves with the following cmdlet against the affected mailboxes: Set-MoveRequest "user@yourdomain.com" -SkipMoving FolderRestrictions Next, the tenant admin may have resume the move request using the cmdlet: Resume-MoveRequest "user@yourdomain.com" This would allow the affected move jobs to continue to make progress. Current status: We're awaiting feedback from a subset of affected admins to validate if our fix successfully remediated impact. Scope of impact: Some admins attempting to perform tenant to tenant migrations and offboarding moves in the Exchange admin center may be impacted. This information may be updated as our investigation continues. Start time: Saturday, February 14, 2026, at 12:48 AM UTC Root cause: A change introduced a code regression to Mailbox Replication Service (MRS), which is causing intermittent failures for tenant-to-tenant migration actions or offboarding moves as the property tags needed to complete the request are not being properly configured. Next update by: Thursday, August 13, 2026, at 9:00 PM UTC

Title: Admins are unable to complete some cross-tenant mailbox migrations in Exchange Online User impact: Admins may be unable to perform tenant to tenant migrations and offboarding moves in the Exchange admin center. More info: While we work on developing a long-term solution, admins may be able to use PowerShell for the affected migrations and moves with the following cmdlet against the affected mailboxes: Set-MoveRequest "user@yourdomain.com" -SkipMoving FolderRestrictions Next, the tenant admin may have resume the move request using the cmdlet: Resume-MoveRequest "user@yourdomain.com" This would allow the affected move jobs to continue to make progress. Current status: We've validated and deployed the fix across the affected infrastructure, enabling the mailbox move to complete successfully. During validation, we've identified that the affected folder was processed as a folder creation bad item and therefore could not be migrated intact. We're validating the overall outcome with the affected users to confirm full mitigation. Scope of impact: Some admins attempting to perform tenant to tenant migrations and offboarding moves in the Exchange admin center may be impacted. This information may be updated as our investigation continues. Start time: Saturday, February 14, 2026, at 12:48 AM UTC Root cause: A change introduced a code regression to Mailbox Replication Service (MRS), which is causing intermittent failures for tenant-to-tenant migration actions or offboarding moves as the property tags needed to complete the request are not being properly configured. Next update by: Wednesday, August 12, 2026, at 3:00 PM UTC

Title: Admins are unable to complete some cross-tenant mailbox migrations in Exchange Online User impact: Admins may be unable to perform tenant to tenant migrations and offboarding moves in the Exchange admin center. More info: While we work on developing a long-term solution, admins may be able to use PowerShell for the affected migrations and moves with the following cmdlet against the affected mailboxes: Set-MoveRequest "user@yourdomain.com" -SkipMoving FolderRestrictions Next, the tenant admin may have resume the move request using the cmdlet: Resume-MoveRequest "user@yourdomain.com" This would allow the affected move jobs to continue to make progress. Admins may be able to run the following PowerShell cmdlets sequentially for migration batches: Set-MigrationBatch batchname -SkipMoving FolderRestrictions Start-MigrationBatch "BatchName" Admins attempting to complete a tenant-to-tenant migration or an offboarding move in Exchange Online receive the following error "PropTagToPropertyDefinitionConversionException" Current status: We've validated and deployed the fix across the affected infrastructure, enabling the mailbox move to complete successfully. During validation, we identified that the affected folder was processed as a folder creation bad item and therefore could not be migrated intact. We're validating the overall outcome with the affected users and continuing to monitor the environment to ensure the mitigation remains effective. Scope of impact: Some admins attempting to perform tenant to tenant migrations and offboarding moves in the Exchange admin center may be affected. This information may be updated as our investigation continues. Start time: Saturday, February 14, 2026, at 12:48 AM UTC Root cause: A change introduced a code regression to Mailbox Replication Service (MRS), which is causing intermittent failures for tenant-to-tenant migration actions or offboarding moves as the property tags needed to complete the request are not being properly configured. Next update by: Wednesday, August 12, 2026, at 3:00 PM UTC

Title: Admins are unable to complete some cross-tenant mailbox migrations in Exchange Online User impact: Admins may be unable to perform tenant to tenant migrations and offboarding moves in the Exchange admin center. More info: While we work on developing a long-term solution, admins may be able to use PowerShell for the affected migrations and moves with the following cmdlet against the affected mailboxes: Set-MoveRequest "user@yourdomain.com" -SkipMoving FolderRestrictions Next, the tenant admin may have resume the move request using the cmdlet: Resume-MoveRequest "user@yourdomain.com" This would allow the affected move jobs to continue to make progress. Admins may be able to run the following PowerShell cmdlets sequentially for migration batches: Set-MigrationBatch batchname -SkipMoving FolderRestrictions Start-MigrationBatch "BatchName" Admins attempting to complete a tenant-to-tenant migration or an offboarding move in Exchange Online receive the following error "PropTagToPropertyDefinitionConversionException" Current status: We've received reports that impact associated with EX1232513 persists. We've resumed our investigation of the issue and have developed and are validating a fix to remediate impact. Scope of impact: Some admins attempting to perform tenant to tenant migrations and offboarding moves in the Exchange admin center may be affected. This information may be updated as our investigation continues. Start time: Saturday, February 14, 2026, at 12:48 AM UTC Root cause: A change introduced a code regression to Mailbox Replication Service (MRS), which is causing intermittent failures for tenant-to-tenant migration actions or offboarding moves as the property tags needed to complete the request are not being properly configured. Next update by: Wednesday, August 12, 2026, at 1:00 PM UTC

Title: Admins are unable to complete some cross-tenant mailbox migrations in Exchange Online User impact: Admins are unable to complete some cross-tenant mailbox migrations in Exchange Online. Current status: We're reviewing support provided information to determine our next troubleshooting steps. Scope of impact: Your organization is affected by this event, and admins attempting to complete some cross-tenant mailbox migrations in Exchange Online are impacted. This information may be updated as our investigation continues. Next update by: Wednesday, July 29, 2026, at 3:30 PM UTC