[Black squares no image on all export types]

I've been exporting files as PNGs and JPEGs and when I do there is no image, just black squares where the image should be - See file attached...

It also happens when copying the layer and pasting it into another file - even pasting it into the same file.

I've tried a solution that was recommended in another thread, Preferences> Performance> Uncheck Enable Metal Compute Acceleration. Didn't change anything.

Thanks in advance.