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M365 Service Health EX1442215
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EX1442215 — Advisory

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

Service degradation
Exchange Online
Networking Issues
Started
29 Jul 2026 14:29 GMT+1
Last Microsoft update
29 Jul 2026 15:26 GMT+1
Data Freshness
Live — 22:30 GMT+1
Impact
Admins may be unable to perform tenant to tenant migrations and offboarding moves in the Exchange admin center.
Incident Timeline
29 Jul 2026 15:25 GMT+1

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.

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

29 Jul 2026 14:32 GMT+1

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.

Next update by: Wednesday, July 29, 2026, at 3:30 PM UTC