I just recently noticed that it seems to be a pretty big deal if you keep your units setup as 1unit = 1inch... this will cause a lot of errors when uploading to shapeways.
The correct scale settings inside 3dsmax should be 1unit = 1mm. This is under Customize > units setp > system units in 3ds. Real important 1unit = 1mm... or there's a big chance your model will fail the automated checks.
I say "recently noticed" because I have already printed two models at 1unit = 1inch... both uploaded and printed fine... but now if I export and upload at that setting the obj or stl will fail nine times out of ten. I was pulling my hair out for a week or so trying to figure out the problem, seems obvious now.