I have a vaguely related, kind of interesting story related to search indexes, but on windows instead of mac. My C drive was was super full for some reason I c

I have a vaguely related, kind of interesting story related to search indexes, but on windows instead of mac. My C drive was was super full for some reason I couldn't understand, and Explorer couldn't tell me where the data was. There was about 100GB just unaccounted for. I don't even use the search index.