Some users’ mailbox migrations from Google to Exchange Online haven’t completed as expected

Title: Some users’ mailbox migrations from Google to Exchange Online haven’t completed as expected

User impact: Users’ mailbox migrations from Google to Exchange Online haven’t completed as expected.

More info: Migrations that have been initiated using Microsoft’s data migration tool are affected. Users who have completed their migrations will observe that Deleted, Archive, and Junk mailboxes show a difference in size after the migration.

We recommend that customers with ongoing migrations, or plans to initiate migrations soon, pause their activity until this issue has been resolved. For customers who have completed migrations since Thursday, March 7, 2024, we ask that you retain internal copies of the affected data to ensure that the items with the impacted labels can be re-migrated following mitigation.

Current status: The deployment of the fix has reached approximately 90 percent saturation. Once the deployment is completed, we’ll provide instructions to re-run the migration batches.

Scope of impact: Any user who is attempting to migrate from Google to Exchange Online using Microsoft’s data migration tool is impacted.

Start time: Thursday, March 7, 2024, at 12:00 AM UTC

Root cause: A code issue was introduced in a recent service update which prevents migrations from Google to Exchange Online using Microsoft’s data migration tool from completing as expected, specifically, the mailbox items with the Deleted, Archive, or Junk labels are not migrated.

Next update by: Thursday, April 18, 2024, at 7:00 PM UTC