Friday, August 26, 2011

MAPI Connections Exceeded

I remember when I worked as a consultant one of my clients suddenly saw a rash of disconnects from Exchange 2003. The culprit was narrowed down to event ID 9646. and ultimately I believe we adjusted the number of connections allows via the registry and all was well. The situation has reared its ugly head again in my very small business environment and has gotten me to revisit both the problem and the solution. Quick investigation of Google hits reveals that this wasn't simply an issue for older versions of Exchange/Outlook either, so it appears it's all still relevant. Here's how I approached it this time.

First of all, Outlook 2010 doesn't show you an error message indicating the problem. It simply shows that the mailbox is disconnected in the bottom right of the window. I tried the standard send/receive to jolt it online, exited Outlook (making sure no processes remained in Task Manager), and checked the profile settings. The user had just rebooted her computer so I didn't bother trying that again. I verified that the computer could ping the server using the FQDN. I tried to launch Outlook using the /rpcdiag switch. It flickered but never actually connected to the server, which helped me to understand that the program wasn't getting a connection to the server at all. I checked the event logs on the machine, which yielded no information. Then I went to the server.

Immediately at the top of the system log was Event ID 9646. I rolled my eyes at this familiar face and began to refresh myself on my options. I knew I could simply increase the max connections but I wanted to take some time and make sure there weren't better alternatives out there, so I took some time to do a little extra reading (one of the luxuries of being in-house IT). I couldn't take too long though because the end user was standing over my shoulder, clearly more than a little anxious to get back to work. I could have also just used TCPView to kill some MAPI connections, but this may have only been a short-term solution and I wanted to be done with this for a bit.

What I wound up doing to solve the issue on a more permanent basis (as well as provide an easy resolution should others begin to experience the same thing) was create a security group, and give it "View Information Store Status" privileges via ESM as per the suggestion in this Microsoft KB. I have also installed exmon to be able to view more detail about connections in the future should this come back up.

No comments:

Post a Comment