Your server administrator has limited the number of items you can open simultaneously
After performing updates on out internal remote desktop server I started experiencing issues with Outlook 2013. Our remote desktop server is configured to not time out sessions, so a session could remain active for a long time. Every couple of days Outlook would stop opening emails, however simply closing and reopening Outlook would fix the issue. I decided to finally resolve the problem.
The error the Outlook would give is:
Your server administrator has limited the number of items you can open simultaneously. Try closing messages you have opened or removing attachments and images from unsent messages you are composing.
After performing some testing it appeared the issue only occurred when cached mode was turned off.
I logged into the Exchange server to see if there was any further clues. I found the following event log message:
Event ID: 9646
Mapi session /0=First Organization/ou=Exchange Administrative Group (FYDIBOHF23SPDLT)/cn=Recipients/cn=Mailbox name with client type MoMT exceeded the maximum of 250 objects of type Message.
The issue was being caused by the per session MAPI limit that was configured on the Exchange 2013 server. By default the limit is set to 250.
To increase the limit perform the following
- Log into the Exchange server
- Open the registry editor
- Goto the following key HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\MSExchangeIS\ParametersSystem
- Right click on ParameterSystem and select new, then select key
- Rename the new key to MaxObjsPerMapiSession
- Right click on MaxObjsPerMapiSession and select new, then select DWORD (32-bit) Value
- Rename the new DWORD value to objtMessage
- Change the value to a higher number (I set mine to 1500)
- Restart the Information Store service
After making the above changes I had no further issues. Not sure why the problem only started occurring after performing Windows Updates.