>rtc files not saving.

Hi all,
I recently started photography and digital image processing and have really been enjoying playing around with rawtherapee. It took me about a month to go through the whole rawpedia making sure that I had at least a decent understanding of the processes and how the tools work etc… Its quite addicting making profiles and whatnot. I have been unable to save any >rtc files and the only curve that remains is the downloaded DCP tone curve that is meant to match adobe. I like making my own profiles and Haldclut profiles etc as i somewhat appreciate the one button approach to batch editing and i kind of like to have a “deck of cards” so to speak to mix and match as a processing jump off point. I use windows 10 version and was wondering if this might be a code error. I can save full profiles and other things just not the .rtc files for curves only… Anyone else have this issue and perhaps a solution? Rawtherapee vs 5.8. downloaded about 28 days ago