Photoshop loader problem

Hi chaps
Got a strange issue today. Loading a PSD file doesn't automatically appear other than the frame it loaded on, but more importantly the layers tab doesn't show other layers, only merged.
It seems to be the Photoshop file, as other ones work ok, but I even tried dropping the new images into the working PSD and it still won't work. they are 8bit, RGB just like the others. doing my head in!
Any thoughts?

This PSD includes any data that could not support in Fusion? Like could be Text, layer fx, mask layers, group layers... I think.

Other possible cause may be PS version, or PSD file header.

Thanks for the tips. I can't find any issues in the file and they both come from the same photoshop.
It really is an odd one.