If you chose the option “Enable build-in frame buffer” and you want to get exr format output including render elements:
Step 1: Please check “V-Ray raw image file”
Step 2: Save image .exr format
It contains all render elements for the image and remember. You HAVE TO check “DEEP EXR” before clicking the save button.
Note: “Memory frame buffer”
Creates a V-Ray frame buffer and uses it to store color data that you can observe while rendering and afterward. If you wish to render really high resolutions that would not fit into memory or that may eat up a lot of your RAM not allowing for the scene to render properly, you can turn this feature off and use only the Render to “V-Ray raw image file feature”.
There is a way to get .exr format output (including render elements) when you use VRAY FRAME BUFFER at Super Renders Farm.
Hope this helps!