In their wisdom setting is now removed. Thanks for that.

Options > Library

Uncheck "Generate thumbnails"

Would you please tell us (and anyone finding this topic in the future) what you figured out?

Nevermind, I figured it out.

My M has been "generating thumbnails" for the past 3 days. Then every time I restart MM it starts "generating thumbnails" all over again from the beginning.

How the heck do stop it from doing this?

It seems to be using up precious CPU resources in doing this "useless" task. I really dont want thumbnails being generated, I dont need them, dont want them, dont want background tasks running all the time, and dont want the space thumbnails take up being used. It will never finish generating all the thumbnails anyway on my NAS, its futile, so why do it? I assume "thumbnails" are the first frame of a video so something can be seen in a list? I use details view so dont want or need thumbnails. How to stop all this?