Some time ago I moved a customers public folder from Exchange 2010 to Exchange 2013 CU5. I flowed this excellent KB from Microsoft¬†http://technet.microsoft.com/en-US/Library/jj150486. But when I got to the part of finalizing the move I got this error when I ran “Get-PublicFolderMigrationRequest | Get-PublicFolderMigrationRequestStatistics” StalledDueToMailboxLock and a message that the job will resume i 5 minutes or so. It turns out that the information store was locking the PF mailbox, after a restart of the information store service the job completed 100% at the next retry.!