Lets see if the Cow is smarter than Autodesk support! (I have a subscription and gave them this problem - they didn't figure it out.)
I do a lot of 3D logos and things that I then composite in After Effects and Toxic. Like any time-crunched artist I render things into zillions of passes - which leads to file management issues. This is why the great guys at ILM developed the .EXR format! You have no idea how excited I was when I found out about it's ability to store more than one image inside of it as channels.
Well my excitement lasted until I ran into this problem; the specifics are as follows:
I render an image (or sequence) out of 3DS Max using Mental Ray. When choosing the render output I select the .EXR file type. I then choose the various channels to bake into the render. I hit render and everything works beautifully! But wait, if I render it again and then look at the channels in After Effects they have turned into junk (specifically, they turn into all kinds of colorful vertical lines and the alpha channel just blacks out, or sometimes also turns into lines). The first time I render a file it is fine, but any time after that it turns to junk...
Anyone have any ideas? I have definitely determined that it has nothing to do with After Effects, but is a defect baked into the render itself.