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I played the original Myst when it first came out, and I wanted to try it again. I like the fact that we can now do a free roam, rather than the stepwise method of transit through the universe. but there's one problem: I generally play these games with an "inverted" mouse control. That is, if I want to look up, I pull the mouse towards me. And down is push the mouse away. Comes from my experience in flying airplanes. Stick back = climb. Stick forward = dive.

Every game I've ever played has an "invert look" setting that accomplishes this. And so does Myst. However, when I turn on the Look Invert, it also inverts the left-right control as well, which drives me nuts.

GOG gives a "fix" for that, in editing the controls.cfg file. However the instructions on where to find that file bear no resemblance to the file structure on my computer. And a search for "controls.cfg" comes up with no hits anywhere on my C: drive. I'm working on Windows 10 64 bit.

Anybody have a clue?
Are you certain those instructions were for Real Myst Masterpiece and not RealMyst?

And to a second thought, did you try creating a blank file according to the syntax?