Hi. Right, the Maya 64-bit is the one I installed. I should add that since my earlier post, I went in to render cuurent frame options and manually set the memory limit to 6144 (6 gigs RAM) and rendered a dense scene and it worked. Took 69 minutes, but rendered fine.

I still don't know why Maya couldn't calculate the available RAM on it's own, but I am still investigating. At least now it's rendering with the available RAM.

Thanks to both of you.

T