I just finished a game-ready character model with a relativily low poly count. I was going to export the object into Mixamo auto-rig when I noticed that my model was missing after I exported the model.
I tested going back to blender to upload my OBJ and FBX versions of the model into a new blender setup, when I did that nothing appeared again.
I checked my export settings and everything seemed to be right (selection only activated, applying different modifiers before export, etc). I also tried to export my model with DAE and my first error message appeared saying "no meshes have been selected".
Its weird because I HAVE selected it and troubleshooted most things, but I have still not found the solution. It seems as if the mesh itself doesn't exist?