Dear all, The problem we have is that the Exchange Optimizer cannot be run on the server. Did any of you ever experience a "There is not enough memory available to complete this operation. - [800FF321]" error when trying to open the Optimizer? We have rebooted the server several times, we stopped unneccessary services, reinstalled Exchange including ServicePack. There is plenty of memory unused on the system and the allocated space for the Registry is sufficient. I am out of ideas. Any help?? We are using Exchange server5.5 on NT 4.0 Million Thanks! Grace