could be your GPU and/or drivers. Vegas has nothing to do with the monitor hookups but if there's a GPU/Driver issue that could cause the problem.

I have had some shaky stuff happen with the dual monitors but not bad or crashes. It seemed to clear up with all the latest drivers.
JJK

Thanks for the thoughts. I doubt that the choice of monitors could have any affect, other than the fact that Windows/the drivers identify the monitors and may have software that adjusts resolution, power consumption etc. from them, since each monitor does have software in it. I do have the latest recommended *production* drivers running on this machine for my Nvidia card.

More likely, it's once again pointing out that, if indeed my crashes are being caused by video drivers that *Vegas* should be working with the *two* major companies to work this out. I've worked behind the scenes in a major software company, and was involved in tracking down these kind of problems on behalf of major clients. It is often very hard to get an accurate crash dump to then allow the two parties to understand the root cause. I would highly recommend that, while tedious, we report all Vegas crashes when they happen, even if repeatedly, on the hope that they are communicating with nVidia and ATI. To be clear, my system *never* ever crashes, except when running Vegas (and likely during this multi monitor mode). I routinely use Word, Excel, all the major browsers, and many other packages to do my work, and only Vegas experiences this. Obviously, they are pushing huge video data onto the the monitor, and managing the memory space doing so. However, to reiterate, I have never had this kind of a thing happen with either Adobe or FCP on my Mac. I'm just ramping up Adobe on Windows, so it will be interesting to see if it shows up there too, with the same graphics card.

JJ, what card/drivers are you running? And when you say, "shaky" what does that mean?

But for now, I'm backing off dual monitors to see if this is continues to be stable.

Don't know if they still do, but SCS was working with ATI/AMD not long ago.

I'd say report the issue to Nividia yourself too. It's not really SCS's job to report to them unless it's something with Vegas, I haven't read (here) about anyone else having issues with duel monitors causing crashes.

Nvidia driver 290.53 with GTX 8800 512 cuda checked in options. The secondary monitor came up black one time and as soon as I clicked the space bar it came up. Never did it again. V10/11 510 32 & V10/11 511 64 installed. HDV and JPG's on timeline with older Quicktime and Cineform files.
JJK

Random thoughts:

The monitor itself shouldn't make any difference as long as the driver properly identifies it. If you look at "Control Panel" / "Devices and Printers" and one of your monitors is called "Generic", then your drivers are out of date. Way out of date. (Or you have a really strange monitor).

If you need more than one video card, make the second card the same as the first. Though Windows will appear to operate properly with two different brands of video cards, it's asking for trouble because you would be requiring Windows to load two device drivers. If a program (like Vegas) makes a call to a driver function in the driver's DLL file - you have no control which driver file will respond.

I thought that with Win 7 Microsoft requires that both video cards be same manufacturer, actually. In any case, I sure would not try mix and match. I've used both ATI and NVidea a lot in multiple displays on many systems for many years - no absolutely clear better/best in my opinion. NVidia used to be better at getting new drivers out but not anymore.

The people who most drive video card development is gamers, a much more demanding use than just rendering video. I'm not a gamer, but I pay attention to their reviews.

I'm using two ATI cards: an ATI Radeon HD 4600 which very competently drives 2 22" monitors, along side a Radeon HD 6570 which I bought to get GPU acceleration; it gave me a 25-40% decrease in render time for about $75. I do a lot of long renders so it's worth it, but not what I had hoped. The last good Catalyst driver is, as of this writing, Nov 2011.

Of course, that doesn't mean Vegas doesn't crash sometimes - it does. But not predictably and not due to any external factor I've been able to isolate, like file type, duration of render, temperature of processor, other activity on the system, etc.

"I thought that with Win 7 Microsoft requires that both video cards be same manufacturer,"

Win 7 doesn't care, but mixing cards manufactured by different companies requires loading different drivers, and that's just asking for trouble.