"No active public folder mailboxes were found" error if Complete-MigrationBatch cmdlet fails a migration batch

Summary

When you migrate public folders from Microsoft Exchange Server to Exchange Online in a multi-domain environment, the Complete-MigrationBatch cmdlet can fail and return a "No active public folder mailboxes were found" error message. This issue occurs if the public folder mailbox and its associated Active Directory user account exist in different domains. In this situation, Exchange can’t locate an active public folder mailbox. To resolve the issue, move the associated Active Directory account to the same domain that hosts Exchange Server, and then run the Complete-MigrationBatch cmdlet again.

Symptoms

Consider the following scenario:

• You migrate public folders from Exchange Server to Exchange Online.
• The on-premises environment has multiple Active Directory domains.
• You run the Complete-MigrationBatch command.

In this scenario, the migration batch goes into a failed state and generates the following error message:

"No active public folder mailboxes were found. This happens when no public folder mailboxes are provisioned or they are provisioned in 'HoldForMigration' mode."

👁 Screenshot of the Get-MigrationBatch command.

👁 Screenshot of the Complete-MigrationBatch error message.

Cause

This problem occurs because the public folder mailbox and associated user account aren't in the same Active Directory domain. For example, the user account that's associated with the public folder mailbox is in contoso.com, and Exchange Server hosts the mailbox in subdomain.contoso.com.

Resolution

To fix this problem, move the Active Directory account that's associated with the public folder mailbox to the same domain that hosts Exchange Server. For example, if Exchange Server is in the root domain (contoso.com) and the associated account is in a subdomain (subdomain.contoso.com), move the account to the root domain. Then, run the Complete-MigrationBatch cmdlet again.

Depending on the version of the operating system, you can use either Active Directory Migration Tool or the Move-ADObject cmdlet in Active Directory PowerShell to move the user between domains.

For example, run the following PowerShell cmdlet to move the user that's associated with PFMBX4 from subdomain.contoso.com to contoso.com:

Move-ADObject -Identity "CN=PFMBX4,CN=Users,DC=subdomain,DC=contoso,DC=com" -TargetPath "CN=Users,DC=contoso,DC=com" -TargetServer dc1.contoso.com