Interesting.
As I said, I don't have any CDPlayer.ini on my C: drive, anywhere. I suspect Windows 10 doesn't allow writing to the C:\Windows directory, and so the file never gets written anymore.
I run my Workstation where I searched with an Administrator account. I just created a CDPlayer.ini file on a separate disc and tried to copy it into the C:\Windows directory. I got a "File Access Denied" popup. I could complete the copy/paste, but I needed to click the Continue button to do so. MC wouldn't cater to that popup I'm sure, so UAC is going to prevent the writing of the file.
You must have changed permissions to allow writing to the C:\Windows directory Matt.