Material Library keeps disappearing

[philvanderloo]

Can someone tell me why every time I reopen a file my custom material library is gone. I'm using a .max scene file with custom materials provided by my VRay dealer. I've been using the materials with no problems but now, for some strange reason, every time I reload the material library it shows in the material browser but when I click to expand there is nothing there.

I have several copies of this file and I've tried loading them all but getting the same result.

I have the same materials in a .mat file and they load fine but I 'd prefer the .max scene file because they are all mapped properly.