Solved 'Out of memory' error when rendering HD video in VP15

In my first reply to you, I said this:

I do have a vague memory of some people reporting a memory problem on the official Vegas forums.
After further investigation, someone worked out that a 3rd party plugin was causing the problem, but I can't remember what it was.

Mercalli is what is causing your problem.
I believe this has been discussed in depth on the official Vegas Pro Forums somewhere and people have already shared their different solutions.
www.vegascreativesoftware.info/us/

Still don't understand why it renders perfectly with the Sony AVC/MXF codec with Mercalli CMOS Fixr/Stablizr applied to quite a number of clips. I will remove all traces of this plugin from the project and see if I can then render it in Magix AVC and Mainconcept AVC.

The result is that rendering with Magix AVC = 'out of memory error'
with Sony AVC/MXF = perfect render
with Main concept AVC/AAC = perfect render

I am careful to ensure that project properties, preferences and render options all match as closely as possible.