Alright so i just created this account because Im trying to import an avatar and when i set the humanoid rig up, unity just stops letting me do things. I can put the model into the scene and i can reconfigure the avatar, but nothing else. It just shows me the option to configure an avatar rig on the inspector window.
At the bottom of the inspector window where you edit the rig, you have a confirmation button, a “Done” button, to confirm the rig selection. It will send you back to the main scene.