Niknesh Yeah that technique only works in 2016 Extension 3 and 2017. I've made a tool to fix this workflow in 2016, and it's free :) https://gumroad.com/l/MayaFWVN
They took Mental Ray out of Maya in newer versions of Maya 2016. In 2017 they replaced it with Arnold. If you search for it there is a separate installer for Mental Ray Maya 2016.
This is an old school hack.... Maya ascii files (.ma) have a header in them that defines what version of maya they are for. Save your .ma file as a copy, then right click and open it in a text editor like Notepad++. You'll see at the top of the file information like: //Maya ASCII 2016 scene //Name: MyMayaFile_Work01.ma…