About a month ago we had an occasion on our 2007 Exchange system that users began getting a very slow and then no response from one of our 2 cluster nodes. We run in online mode (FYI) so they do get the message. We were able to get them back in by failing the node over and then back or just leaving it on the failover node. (Single copy cluster) Suppporty has had us do everything from disabling Chimney all over the place, re-running prepareAD, decreasing pagefile size, disabling antivirus, adding some permsissions, added all of the mail servers to the Exchange servers group that I think was just a group left over from when we had a 2003 Exchange server during our migration, etc etc. We are not yet on SP1... Yesterday we were watching perfmon and it happened. The only thing we saw was a spike in RPC calls just before it happened. We've tried everyhing they've told us to do. We are digging around and found that the most items recomended for any of the critical path folders (Inbox, sent items, calendar, contacts)is between 2500 and 5000. In reporting on what we actually have, we find that we have 15 clients with over 15,000 items in just their inbox alone (yes, that's "each"). All totaled we have around 190 that are over the 2,500item mark and of those, 75 are over the 5,000 item mark. This is just the inboxes and does not include their sent items which are quite large themselves. 21 Users have over 1GB (size)in their inbox alone with 2.5 GB being the over-all leader in that category. A lot of this can be contributed to the fact that we don't have archiving working properly. We just discovered the whole "archiving by modified date fiasco" which hurts pretty badly. Currently researching Ent Vault. Meanwhile, could these types of numbers be causing our problems at high load times? Typically lunch is a high load time and it's happened at 4:30 PM (on a Friday) 1:45PM 12:10 PM 11:20 AM 1:08 PM 11:20 AM 11:10 AM Until we are able to get these people archiving, we are unable to set size limits so we're stuck there....for now