As far as I can understand reading the replies, making a defult UI theme for Corona is more complicated than just making max automatically convert all material slots into corona materials, but I think alot of users are used to this (from vRay). I'm certainly missing it.
Hi guys ! I do not think that it is complicated issue ...I have just tried make something like this.....We should place it (MAX.corona folder) into C:\Program Files\Autodesk\3ds Max (version)\en-US\defaults location ...then open 3ds Max session.... choose Max.corona from Custom UI and Default Switcher list ..press set ..and ...vuala..it can be now possible set corona renderer and material editor as default set !! Now it doesnt change empty material slots into vray or another engine materials while reseting material editor but keeps only corona materials!! NOTE : this can be run only on max 2014 and higher versions ! Concerning corona version I made this set using corona 3 update 2 version and dont know whether it compatible with older version!