Ok - not exactly. But there are a few things you need to configure on your SQL box if you want SQLMail to follow the rules of MAPI multithreading.
Before we get too deep, a couple notes:
Avoiding crashes and hangs with SQLMail
Let's discuss that last one a bit, since there's a lot of SQLMail KB articles out there that mention running xp_startmail as part of a workaround. The folks that wrote those articles just aren't aware of what SQL does when xp_startmail is run and the effect it has on MAPI.
The thing to understand is that SQL uses a lot of threads. There's a thread pool that sits around ready to service various jobs. When SQL is processing a script, as it gets to various commands it will grab a thread from the thread pool, have it execute the command, then return it to the pool. So in the course of processing a single script, SQL might use a number of different threads. Suppose you have a script that executes xp_startmail, xp_sendmail and xp_stopmail. Each of these procedures could get handed to a different thread!
Why is this bad? Because xp_startmail is essentially a call to MAPInitialize and xp_stopmail is a call to MAPIUninitialize. So by using this commands, we will end up initializing MAPI on one thread and uninitializing it on a totally different thread. And this would be bad - very bad - crossing the streams bad.
Fortunately, xp_sendmail will call MAPIInitialize/MAPIUninitialize on its own, so we don't need xp_startmail or xp_stopmail at all!
Every SQLMail crash and hang I've debugged was resolved by implementing the above recommendations.
The December 2007 Release (build 188.8.131.523) is live: http://www.codeplex.com/MFCMAPI
Here's the change list - see the Issue Tracker on Codeplex for more details, or look at the code:
Yesterday, a new Developer Support engineer started here - Rick Hallihan, of OneManShouting fame. We snagged him away from the Home Server MVP program. (I hope we didn't make any enemies in doing so!) We're gonna teach him up good in MAPI and he'll in turn learn us all he knows about Home Server.
Speaking of Home Server, I don't usually spread links, but I thought this was funny:http://www.stayathomeserver.com/default.aspx
It looks like a parody, but I've been assured it's a real site run by the Home Server team. Not many videos up there yet, but the "Home Sweet Server" vid is great.