I've been playing on a C64c (NTSC) via Ultimate II+. I'm not sure if this was a bug that happened or something with the hardware made "general disk" go away, but essentially got stuck on a white screen after casting a spell to leave the Old Ruins. Because of that, I didn't do the order of operations correctly to properly recover my save progress with "Quit Game" and lost 3 hours :(
This video link will be valid for maybe 30 days until Twitch archives it if you want to look at it and see what might've went wrong.
https://www.twitch.tv/videos/2373526841?t=04h13m48s
I've been really enjoying the game otherwise and think I might switch to the MiSTer or VICE if I can get the .d64 save disk to read and make up the data loss. I also have unruly cats and they've concerned me by walking on the C64 and potentially locking things up, too. :D