Same problem - skp 2021, vray 5.1 , also 5.2 skatter 2.04 not rendering objects “render only”
I’ve reinstalled skatter, clear library folder and download again, tried 2 versions of vray and none of this worked.
I’ve solved problem by unistalling 2.04 and downgrade to 2.03
link here: [Release] Skatter 2.0.3