I use Microsoft Security Essentials... but I unless I reboot daily (scheduled), I get static with MC within a few days. I have clearly matched the static from MC to MSE. I blame MSE....
Have you tamed MSSE?
http://wiki.jriver.com/index.php/Taming_Windows_DefenderI use Windows Defender (and MSSE long before it) and have never had any similar issue, certainly not with audio. It sounds almost like it is an incompatibility between MSSE and your DAC. You didn't say which one, but the fact that it is cleared by a reboot strongly indicates that the audio
driver is involved somehow.
MC itself doesn't do anything special at bootup, except maybe launch itself. But if it was some kind of conflict with MC, then restarting just MC (including exiting the tray Media Server, if enabled, of course) would have the same effect.
In any case, my gut instinct says that, if it is a conflict with MSSE, then it is between your DAC's driver and MSSE, not MC and MSSE.
Regarding this:
proceed or disregard?
I've seen that once or twice before (with MC and at least one or two other applications). That's how Microsoft collects data on applications to improve MSSE/Defender's heuristics. If anyone sees something like that, from Microsoft's or another AV vendor's product, you should absolutely submit MC, and make sure to mark it as "safe" if they ask for your opinion on the situation.
AV applications are... Well, I've gone into details before, but they are riddled with "exceptions for" and "special casing for" all sorts of applications. Without it, applications as common as Microsoft Word and Adobe After Effects would
never be able to run properly with AV interfering (and you can see this sometimes when you run betas of even big apps like those). The way the AV vendors collect information on what apps they might be "blocking" (or need to block) when they haven't seen the product before, is though these mechanisms. This is a good way to get them the information they need to make sure their product doesn't interfere with MC (or, at least, not as badly).