I've done 10 broadcasts using my current preset. For what it's worth, I have had this issue happen with other presets, but I'm using only this preset as a quantifiable sample size.

Of those 10 broadcasts I have had the following occur on 5 of them: (If it matters it was broadcasts 1, 3, 6, 7 and 10)

Mid-broadcast vMix will suddenly crash and instantly restart.

The time of the crash happens seemingly randomly. Sometimes it's 15 min in, sometimes it's 40. It is basically 1 crash and then...that's it. It doesn't seem to happen again.

I have let this preset run for extended periods of time outside of broadcast and it never crashes. It ONLY crashes mid-show...which, ya know, is real swell.

I use an external encoder (AJA Helo) if that matters -- but the AJE Helo has no issues, it just keeps broadcasting (black screen at that point).

I have sent a number of error reports to vMix and Martin seems to think I have a graphics card issue, but I have stress-tested it numerous times AND replaced it. But still...same issue...(insert shrug emoji)

My question is, has this ever happened to anyone else and/or does anyone have any recommendations to try and fix this? It's obviously super frustrating because I can seemingly only duplicate it by broadcasting.

Thanks in advance everyone!

Curious - did this get resolved? If so, what was the culprit and ultimate solution?

You don't mention what graphics card initially had the problem or what you replaced it with. I would have to guess a thermal problem or the Power supply on the system can't deliver enough power when the card needs it, I have seen this happen on a system when pushed hard.