UV Unwrapping Missing Textures

I’ve recently been learning UV unwrapping for texturing and whatnot, but I have come across an issue. I’m still learning how to properly unwrap more complex models, so I’m not too experienced in general, but one thing I’ve frequently come across is what appear to be missing textures, or I’m not unwrapping everything in the model.

What will happen is I will unwrap a model by selecting all sharp-edges and marking them as seams, then UV unwrap the mesh. I then create a new texture using the default grid texture in 4K, but upon applying the texture, not every part of the model is covered by it and will simply remain grey. I soon after realized that selecting the faces that aren’t textured don’t seem to appear anywhere in the UV map, so I’m guessing they weren’t unwrapped in the first place.

So far I haven’t found any information on this issue online, so I’m asking here if anyone else has encountered this issue and knows how to resolve it. Keep in mind that I’m very new to UV unwrapping and am thus inexperienced in this subject.

Before you performed the unwrap procedure, did you verify if ALL faces were really selected? Was the x-ray mode on when you selected them?

It seems like they were not.

Yeah I started experimenting shortly after posting this, and I quickly realized that.

Correct me if I’m wrong or if there’s something I’m missing, but you are supposed to select ALL the faces, not just the ones marked as seams, before unwrapping, because that’s what I did.

Correct, yeah. Mark your seams, and then select all - unwrap.

Can you show some screenshots? Will help visualise what the problem might be

Yes, you need to select all. The seams are only to tell Blender where the cuts are.

I’ve pretty much taken care of it now, I’m probably going to delete this.