Running Exchange 2010 Version: 14.01.0289.001. We did some maintenance last night on our filers in which we had to shut down our Exchange servers. Upon coming in this morning we are seeing 100 CPU utilization on our Exchange server. If I shut down the Microsoft.Exchange.Imap4.exe server the CPU goes back down to 30% or less. The minute I start it back up again it starts consuming more CPU. We have about 100 users connecting to our Exchange without cache mode so the store.exe is typically at about 10-30% during peak times, but the IMAP seems to make the server CPU spike. Any suggestions?Jeff D

You obviously have Update Rollup 3-v3 for Exchange Server 2010 Service Pack 1 (while the last digit of the build number should be 7). This rollup fixed a lot of IMAP4 issues. RU4 does only fix a client IMAP4 problem. RU5 is scheduled to be released by the end of this month. Exchange 2010 SP2 will be released sometime in the second half of calendar year 2011. Perhaps some more IMAP4 issues will be solved by then. In the meantime you could look into Client Access throttling. While I'm not at all sure if that will solve your problem, the idea of this functionality is to ensure that no one user can tax your Exchange Server Exchange 2010 Client Access Throttling http://blogs.msdn.com/b/pepeedu/archive/2010/01/13/exchange-2010-client-access-throttling.aspx Exchange 2010 Client Throttling http://www.shudnow.net/2009/09/26/exchange-2010-client-throttling/MCTS: Messaging | MCSE: S+M

Jon-Alfred’s suggestions are good. I also suggest you run Exchange Best Practices Analyzer for your Exchange Server and check event log whether there is any related information. Thanks, Evan Liu TechNet Subscriber Support in forum If you have any feedback on our support, please contact tngfb@microsoft.com

Thank you for your suggestions, I will give this a try.Jeff D

Hi Jeff, Any updates on this issue? Thanks Evan Liu TechNet Subscriber Support in forum If you have any feedback on our support, please contact tngfb@microsoft.com

We are still running into this issueJeff D

We tried the following: Set-ImapSettings -server "servername" -MaxConnections 200 -MaxConnectionFromSingleIP 200 Still consuming high CPU utilization, I have a call open with MS. I will fill in the details once I get more information from lead tech.Jeff D

Please come back with your findings. IMAP4 has traditionally not been Microsoft's apple of their eye. That works a lot better with MobileMe and Mac clients: "Exchange for the rest of us" (Steve Jobs). Still I find it impressive that Microsoft puts so much work into IMAP4 support. IMAP4 and Exchange 2010 RTM http://blogs.technet.com/b/exchange/archive/2010/05/06/3409925.aspx Better IMAP in Outlook 2010 http://blogs.office.com/b/microsoft-outlook/archive/2010/02/05/better-imap-in-outlook-2010.aspx MCTS: Messaging | MCSE: S+M