One of my users (my CEO of course) started experiencing an issue with Outlook on his computer. He will either not be able to send messages or even save a draft of a message. Outlook basically becomes useless to him until he restarts his computer. I've noticed that around the time this happens we get Event 9646 on our Exchange 2010 server referencing my CEO -
Mapi session exceeded the maximum of 250 objects of type "objtMessage".
I know there is a registry edit that you can do on your Exchange server to increase the limits but I'm hesitant to implement it since it is only happening to 1 of 80 users. Is there other troubleshooting that I can do on his mailbox to determine what is causing the issue?