Image trace just produces non-editable image

Hi All

I'm sure I'm missing something basic, but every time I try to use image trace all is get is a non-editable (but traced) layer called "image trace" instead of the original image. If I try to select a path, I can only select the whole image. There appear to be no editable paths. I have tried it again and again, followed the written instructions and watched videos but I just can't see what I am doing wrong. Any ideas?

Thanks

Caspar