[Juris Berzins]

Hi. Just stepped into that issue, lost one render, and made quick research. PSD works fine of course, but the only problem is file size and not all render farms supports such big render file formats as PSD.

Uncheck “AlphaChannel” check box in RenderSettings panel under SaveRegularImage. It does the trick – diffuse renders normally. I can’t explain in any way, but it works.

If You need Alpha just add CompositionTag with one ObjectBuffer to all your objects and include it in the multipass tree as a separate pass.