Oldsmoke's question is very important: if you have something which requires Quicktime, for instance, that could be causing the problem.

To reduce the problem, try dragging just one clip from the shoot to a new, fresh timeline. Then, without doing anything, try rendering that clip, using the exact same codec and template that you used for the renders that are crashing. If that doesn't crash, then we know it is not a problem with the source footage or the render codec, and we can instead focus on fX, compositing, etc.

I would also suggest that if you have the GPU enabled, that you try to render with it disabled.

Seems to happen on a variety of projects but I do have a mix of 4k (from an AX100), EX1, HDV and .pngs in the current one.

GPU rendering is always off otherwise Vegas goes very unstable on me.

Note: I can always fix the crash problem temporarily by restarting the system.

Maybe the PNGs are giving some troubles?

I've never had problems with pngs in the past. They were always the preferred graphics format in Vegas. Also it seems weird that a restart temporarily solves the issue. It seems another program being opened during editing could be causing an issue. Anyone have a link to the previous Vegas 13 build? I never recall having render crashes until the latest version.

there you go:
vegas b373

what format are the 4k files (and how many files do you have in the project)?

Have you had any operating system updates lately? Sometimes Windows Update (and others) make changes that indirectly affect Vegas. Video drivers and Quicktime updates are notoriously hazardous to Vegas' health.

What are your input video formats? The free Mediainfo program is a good place to find out.

Part of the problem may be heat.
Clean your fins and fans, and see if it improves.

I did do some net framework updates. I will try the older version of V13 and report back if it solves my problem. I don't believe heat is an issue since a restart immediately solves the problem. Thanks everyone for your input.

I've had the same kind of issues with my 570 and believe the problem is with VP 13 NVidia GPU rendering. I completely solved my crashes by setting the Dynamic Ram Preview to 0.

It makes no sense that this would be involved, but bugs are nasty.

I just had the problem and uninstalled Vegas and re-installed the earlier version posted in this post. No rendering problem after doing that. Time will tell. Not sure what I had the dynamic ram set to so I'll keep an eye on that as well.

Spoke too soon. Hard crashes when selecting render to a new track. Dynamic ram is set to zero. Back to the drawing board.

Set Dynamic RAM preview to 500 MB and leave it there. Setting it to zero can do strange things.

Oldsmoke mentioned the still images, but the focus was, unfortunately on the format (PNG) rather than the resolution. Year ago, Vegas crashed all the time when it was fed lots of high-res still photos, even when they were in the preferred PNG format. Supposedly that problem got fixed, but in my experience, all they did was reduce the problem, rather than eliminating it.

So, as a troubleshooting step, try this: save the project under a new name. Then, remove all the still photos from the project, and just leave gaps on the timeline. Go to the Project tab and remove all unused media from the project. After having done this, try the render and see if it completes without failing.

As for heat, which has already been mentioned, you can easily download and run a utility which measure the heat in your processor. It you are getting close to the maximum, you will easily be able to see this.

One other thing which can cause problems are 3rd-party vendor fX. Are you using any non-Sony fX?

Try setting Dynamic Ram to 0 and see if it does "strange things".

This has worked for several other people using NVidia GPU's. I've been running with it set to 0 for several months with no render crashes and no evidence of any strangeness.

Here's some other people for whom it worked:

http://www.sonycreativesoftware.com/Forums/ShowMessage.asp?ForumID=4&MessageID=914854

Try setting Dynamic Ram to 0 and see if it does "strange things".You may be right. Changing this setting has worked and/or NOT worked ever since it was added to Vegas a decade ago. Its effect on the stability of Vegas has changed with every release. Put another way, with past releases, the zero setting has helped, but it has also caused problems for some users.

The only reason I was trying to be adamant about setting it back to something other than zero is that he'd already tried that and the zero setting didn't work, and therefore I thought it would be better if he put it back to something normal, so its zero value didn't cause some other problem with a later project (it persists from project to project, until you change it).

Lately it's gotten to the point where I could not render anything even with a restart. I looked at the latest software installs and two versions of Microsoft Visual C++ 2013 Redistributable were installed recently when I installed GoPro software. I uninstalled both versions and the GoPro software and I'm rendering right now. I'll have to see if this is a permanent solution but has anyone had similar problems?

I also tried a test project where a removed all stills and it did not solve the issue.

Thanks, Marc