Hi all. Asking the community for opinions and advice. I've opened tickets on this rare issue in the past, and SmarterTools support has been attentive to the tickets, but it still occurs, albeit rarely.

Yesterday, a few customers called/texted that they couldn't get mail. I attempted to login to the SM server and it was practically frozen. It took about ten minutes just to login and get to taskmgr. SM service was using 99% memory (19GB) but relatively low CPU (24%) so I killed the process and restarted SM. Problem resolved. Today, server is chugging along just fine and SM service is using 5GB memory which is average daily usage.

My hunch is that MAPI is causing this but I have no real evidence to support the thesis. This is my hunch because in that prior to MAPI (two/three years ago?) this never happened in the almost 16 years of SmarterMail usage. In 2022 it happened and ST recommended adding memory so I upped it from 16gb to 20gb. In 2023 the recommendation was to update to latest build which upgraded from 8251 to 8601. Another recommendation was to install and run a dotmemory and dotTrace diagnostic tool when the memory hits 99% but at 99% memory the server is generally unresponsive and the overriding need is to get mail services back up and running ASAP. So, what recommendations does the SM community have?

Server is Win2012R2 (yeah I know... new server is on the docket)

8 vCPUs, 20GB memory, plenty of disk space.

Build 8601, roughly 350 active accounts, 100 MAPI, 40ish ActiveSync, the rest IMAP/webmail.

Thanks for any thoughts.

Matt