I been having this error in my event viewer for a few years I think. I read that I can increase the Named Props Quota in the registry. But the right move would be to move all mailbox's to a new database and move them back to the old one. My "priv1.edb" is around 45gb. Used space on the drive is 69GB and free space is 33GB. What I want to know is do I have enough space on this drive to move mailbox's back and fourth? I never movied mailmox's before or created a new Database(store). Any help would be appreciated. Can i set the " Named Props Quota" to 16384 and Dismounted and remount the store and buy me a few days of time? What if the store does not remount? I am already getting the "A non-delivery report " in the event viewer now.