Exception: Malformed Avatar, breaking the VRChat SDK builder. Please help

So I just finished making and uploading 1 avatar and felt like creating a second. I used a template, modified parts of it in blender, ensured the armature and weightmap were good, fixed model for good measure, exported as FBX, all the stuff I’d learned to do for the first avatar.

In Unity I uploaded it, put some Poiyomi shaders on it, locked them, gave it a humanoid animation type, ensured the bones were all correct, gave it the VRC avatar descriptor, and some dynamic bones. All and all, much smoother than the 1st time when it was a learning experience.

I open the VRChat SDK to build it, but the build window is just grey. I can click settings and content managed, but the builder is blank. Then I check console and see 999+ errors all labelled the same thing:

I can’t find anything about this, hoping someone here knows how to fix this.

For any others who enocunter this, someone on Reddit found the answer. Switching from the SDK 2.0 to 3.0 fixed it.