Theme layouts disappeared

I’m not sure how this happened. When I began using Hugo, I created a folder called “Hugo” with two folders inside it, “Sites” and “bin” (the latter with all Hugo binaries). I converted two Jekyll themes to Hugo and put them in that “Sites” folder. I forgot about them, but I checked on them today and all the layout files were missing (I have upgraded the binaries several times, but somehow never checked the Sites folder). Does anyone have any idea what could cause this?

I haven’t yet figured out what happened. But I redid the themes from scratch.