System Information
Win7
Nvidia Quatro FX 4600
ATI Radeon 3000

Blender Version
Not sure if it ever worked, but just tried 2.7

Short description of error
Open two copies of blender on same pc, only grabs render frame from one program or none

Exact steps for others to reproduce the error
I am trying to render a stereoscopic animation, I don't know if blender can do this (game engine can do stereo) in one pass..
Basically I have two cameras and a short animation, rather than waiting for left to render, I opened blender again on same pc and started rendering the right camera at same time.

I got a garbled mess with mpeg options, dropped/black frames for both files.
Then I tried PNG and noticed I was getting the same image for left and right (but individual manual shots were correct, render button, not animate) and then I started getting black frames while I was checking image output.

I think I even tried one blender copy on cpu and the other on cuda and still nothing useful.

If screen/vid card makes a difference, one blender window is on nvidia and the other is on the ATI card.

Thanks for your time! Love this program!

I'm not sure if this ever worked.. (I *think* I did it before though on an older version), but it would be great if it did