Can't create prefab from blender model

Good day.

Look at the inspector when you select the "Cube". It does not have a Mesh renderer (at least not the standard mesh renderer). It says it have a "Skinned mesh renderer".

(first time i see this, but as you should do, i went to Unity manual and read this 1st line)

Unity uses the Skinned Mesh Renderer component to render Bone animations, where the shape of the Mesh is deformed by predefined animation sequences. This technique is useful for characters and other objects whose joints bend (as opposed to a machine where joints are more like hinges).

Sooo, this is a "body part" of your prefab, it can no exist by its own without the Armature.

So if you want a prefab, you need to create a prefab of the armature with only this cube child.

Bye!

PD: GO FIND THE SOLUTIONS BY YOUR OWN. I had the answer in 40 seconds, and was 1st time i saw this component.

Bye again!