Apologies, I sounded a bit presumptuous in saying it certainly wasn't File Explorer at all, I just didn't want to put full fault on it because it seemingly works with all other files/games/etc., but files connected to osu (skin files specifically) when interacted with make File Explorer fail. That said, the Event Viewer says it's a problem with Explorer, but again, it solely happens with osu to my knowledge of everything else I've interacted with in File Explorer.
I did as you said, I both closed osu and I unmarked the read-only box, I applied it and hit Okay, but when I went to check if it actually unmarked, the box was marked. I unmarked it a few times and just left it. Did the simple check to see if it would crash and still the problem continued.
On an old PC I had, I never had the problem to keep osu open (let alone this problem at all), I would change things and use the skin reload shortcut, but since this issue first began I thought of closing osu and did, but it still didn't change the outcome.
If you need a screenshot of my Event Viewer or anything, let me know. I appreciate all help here.
Edit: I use Windows 10 and the latest osu client if that helps any.