Exchange 5.5/Archiving

Hello Everyone,
We have Exchange server 5.5 we replaced the Hard drive to a larger capacity. We stored everyting from our backup and all is well. The problem that we are having our 250 Outlook Clients users cannot run their Archive it fails. Cansomeone help me on this issue please. I have search all the KB in Microsoft and no sucj lack. Please help. Thank in advance. -ralwyn