I had a call with a client yesterday regarding their Exchange 2007 mailbox server crashing with Dr. Watson errors. Their deployment is a Single Copy Cluster and to make matters worse when the error was occurring the cluster would not fail over.

This problem started for them when Mac users upgraded to the newest version of Snow Leopard. Based on conversations I had with them I’m guessing Snow Leopard was causing a high level of traffic to the Exchange 2007 mailbox server and caused the server to fail. I have actually seen this as well when an Outlook plug-in goes rouge and causes a high level of RPC connections to the mailbox server. The mailbox server in essence becomes unresponsive and users can not connect.

Asking about their updates they had not updated the Exchange servers with any Exchange roll ups for some time. I advised them to update their servers, which they did by deploying RU 9. They also asked Mac users not to use Snow Leopard for awhile until they get this thing out of control as their mailbox server was crashing every 20 minutes give or take. 

As a note the admin there said he was also familar with a another Exchange admin having the same experience.  This may not be directly related to Snow Leopard and Exchange not being updated but there is a chance. 

I’m thinking the RU9 will help, but I’ll let you know if the problem continues!