Hi: a trick I pull when Vegas refuses to render is as follows:
1 Save your problematic project as
2 Select the entire timeline and hit delete
3 Open a second instance of Vegas with the problematic .veg file
4 Select the entire timeline and copy and paste this into project
5 Try to render this
I’m using Windows 7 64 bit,- but this may be worth a try as it has got me out of a hole several times.