A simple solution:
hi there, i’m not a pro when it comes to Vegas but i encountered the same problem when rendering a project to WMV output. One day it works the next it goes “low on memory” but i think i found a simple solution (you gonna laugh but it worked):
i just started a second instance of Vegas with a new project went back to the one that always crashed (w/ low on memory error) marked the entire project files and copied (Strg+c) and pasted them into the new project. Viola, rendering worked again.
Don’t ask me what the problem is, but it seems that in my case after a crash the project was corrupted and rendering was impossible. I had the same experience that it worked one day and the next it didn’t. I hope this helps. Cheers