Mixamo Upload Problems
Auto-rigger fails or the character looks wrong
Also known as: Mixamo T-pose · Mixamo auto rigger · Mixamo textures missing · Mixamo upload FBX · Mixamo character bending · Mixamo animation wrong
Quick answer
Mixamo's auto-rigger works best with a clean, single, human-shaped character standing in a T-pose, arms straight out, facing forward. If the result bends wrongly, check the pose and the placement of the markers for the chin, wrists, elbows, knees and groin. If textures are missing after upload, zip the FBX or OBJ together with the texture files, and download with Skin selected to get the mesh back with the rig.
How to fix it
Use a character with a reasonable polygon count, closed and without separate floating parts such as loose hair, and apply the scale in your 3D tool before upload. A character with the arms close to the body, a skirt or cape often deforms badly. Mixamo's animations work on its own skeleton, so check the bones in Unreal, Unity or Blender and use retargeting for characters with a different rig.
Tools that use Mixamo Upload Problems
See also
Animation Retargeting
Transferring animation between skeletons
Avatar (Humanoid Rig)
Unity's bone mapping for humanoid animation
Skinning
Binding a mesh to a skeleton
Weight Painting
Painting how bones move vertices
Bind Pose
The neutral pose a mesh is skinned in
Character Stuck in T-Pose in Unity
Animation does not play on the character
T-Pose vs A-Pose
Neutral poses for modeling and rigging