While removing unrelated programs, I noticed 'Skywind version 0.9.0.1 (PR)' still listed in my Apps & features page. It has a size of 12.5 GB, which is what Skyrim was at at the time. It was installed 3 years ago and obviously a very outdated alpha copy.
Anyway, I uninstalled Morrowind and would like to get these supposed 12 GB back, but the uninstall button on this list points to a regular Skyrim uninstaller that it can't find regardless. Recently, I completely cleared and reinstalled Skyrim, so any remnants of Skywind as a mod there are 100% gone.
Tracked down my Skywind archives and there are a great many asset packs, along with an installer. I wasn't comfortable manually installing things at the time, so that's likely where this problem came from. It does not have an uninstaller with it and I can't try to reinstall without doing Morrowind first, which I'd rather not do regardless.
Probably just a registry error that can be safely ignored, those 12 GB not actually being used at all, but it'd be nice to have it corrected. Searching regedit just uncovered references pointing to unins001.exe, which doesn't exist on this computer. Unins000 is the Skyrim uninstaller, so it may just be a duplicate that was created when installing, but it obviously won't do the job now, anyway.
Any ideas would be great. This project is amazing, undoubtably, but its older incarnation is giving me a headache.