Public Folders Migration

Hello,

I was migrating users and pf from Exchange 2007 to Exchange 2013. Unfortunately after migrating users, E2007 died. I am trying to setup public folder mailbox and public folders on E2013. However, every time  I try to setup PU mailbox I get message:"Error. An existing PF deployment has been detected. To migrate existing PF data, create new PF mailbox using -HoldForMigration switch." I cannot find any traces of existing migration, so how can I stop it. I was able to recover public folders database from dead E2007, how can I transfer data to new E2013?

Thanks,

Kris