A while ago I downloaded the Locomotion pack from Mixamo and want to use it with a character I created and rigged in Mixamo Fuse but when I can’t get them to work, my character is stuck in the t-pose. I tried copying the avatar from the animation’s fbx. The animations from the packs I bought on the Asset Store work fine though with no fussing. What step am I missing?
If you bought Mixamo’s Locmotion Pack on their site, you received FBX file(s) targeted to a specific skeleton. If you’re using Unity’s Legacy animation system, you can only apply those animations to models with the same skeleton. If you’re using Mecanim, import your models and the Locomotion Pack FBX file(s) as Humanoid. From your description, I’m guessing that the Locomotion Pack’s FBX file(s) aren’t imported as Humanoid.
Watch this video. He explained it all. Unity Animation Retargeting: How to use animations with a wide variety of characters - YouTube