I have just started transferring image files from the 2 internal drives of the editing PC to a new external drive.
After clearing out many GB of images I found that 'c' drive, operating system and programs only, no cache storage or image storage, only had about half of it's capacity despite only using about 2 gb for programs.
Further looking into the drive reveals 14,385 files that range between 6,000 and 10,000 kb each and all are sequentially numbered but mostly all in the last few months since the last update.
The files are all called --- usr_report#####.txt ---- and are being deposited directly into 'c' drive.
They contain a ton of digital gibberish as well as some recognisable elements of Capture NX adjustments.
A bit of a google seems to show up others having similar experiences.
There appears to be no control over whether the .txt files are actually created or where they should be written to in the options menu of CNX.