Troubleshoot Migration Synchronization Failures

Applies to: Office 365 for professionals and small businesses, Office 365 for enterprises, Live@edu

Topic Last Modified: 2010-12-16

After mailboxes are initially migrated, the migration process logs any failures that occur during the incremental synchronization between the mailbox in the on-premises messaging system and the cloud-based mailbox. These failures are listed in the Error Report for Synchronization Failures. To display this report, select Manage My Organization > Users & Groups > E-Mail Migration. In the E-Mail Migration pane, click Show error details.

Note Unlike other migration errors, synchronization failures aren't included in status e-mail messages.

What happens when a synchronization failure occurs?

A synchronization failure prevents the retrieval of new e-mail sent to the on-premises mailbox. This means e-mail sent to that mailbox won't be copied to the corresponding cloud-based mailbox until the synchronization failure is resolved.

Suggested solutions for common synchronization failures

The following table describes common synchronization failures and how to fix them.

Synchronization failure	Troubleshooting suggestions
The migration process couldn't sign in to the user account on the on-premises messaging system.	Confirm that the account on the on-premises messaging system still exists. Verify that the current user name and password for the account are the same as those used in the CSV file when the mailbox was initially migrated. If you're using an administrator account with super-user credentials: Verify that the current user name and password for the administrator account are the same as those used in the CSV file when the mailbox was initially migrated. Verify that current user name for the mailbox is the same as the one used in the CSV file when the mailbox was initially migrated. Verify that the administrator account has the necessary permissions to access the user account.
The migration process couldn't connect to the on-premises messaging server.	Verify that the messaging system service is running on the on-premises server. Verify that the on-premises server is available and that you can connect to it. Tip Use an IMAP or Exchange client to connect to the on-premises server, depending on the type of migration you are running. Use the same connection settings that you used when you ran the initial migration batch. Or use the PING command to test whether you can communicate with the on-premises messaging server.
The user's cloud-based mailbox is full.	Free up space in the user's cloud-based mailbox.
On-premises mailboxes are no longer being synchronized with corresponding mailboxes in the cloud.	Verify that the messaging system service is running on the on-premises server. Verify that the on-premises server is available and that you can connect to it. If you've verified that the on-premises server is running and you can connect to it, start a new migration batch for the mailboxes that aren't being synchronized. This will cause the migration system to try to synchronize the mailboxes again.