If you’ve run into a similar error message when exporting a video-captured emote in Roblox, here’s a simple fix that worked for me.
1. Save the Animation
Save the animation so it appears in ServerStorage
2. Delete unnecessary folders
Under the animation save, delete all !folders! except “HumanoidRootPart”
The children should now look something like this:
3. Reupload
Export this new animation to Roblox and it should be good to go for uploading!
Note: This is what worked for me. I am unsure if there are simpler ways.