cbtsam Loc: Monkton, MD

I have been using the HeliconFocus "Pro" program for several years now, on an iMac. Just today, I ran a stack, and went to save it as a ".dng" file, as I have routinely done for years. This time, I got the following message:

"To be able to save in DNG format, please open RAW files and select RAW-in-DNG-out loader in
RAW Development Settings under source image list."

I have no idea how to follow this instruction.

I can still save save in .tif format, but then, when opened in ACR, it doesn't know and cannot find the lens I am using, a 105mm Micro Nikkor VR f/2.8, so I can't set those optical variables.

Any help to solve this would be very much appreciated.