I’ve previously reported this problem here:
It seems that changing animation BPs can corrupt them. The only way I’ve been able to fix it is to completely remake a new animation BP, which is very time-consuming for complex BPs.
The symptoms I see when this happens is:
Opening the project and running in the editor will have the player mesh unresponsive, usually in the base pose (for mine, it’s a T pose) - no animations. It can attach objects if you pick them up, but there’s no movement.
If I look at the animation BP, it usually shows that it is already compiled and up-to-date – but the little preview will be in the correct stance, instead of the T pose. If I compile the animation BP, it will actually change the player mesh, and it will now work running in the editor.
However, when it’s in this state, I can’t make a compiled version that works; the player mesh is always in the T pose and won’t animate at all.
The above often creates crashes – sometimes opening the editor, sometimes closing it after modifying an animation BP, etc.
Copying the animation BP doesn’t fix it. The only way I’ve found is to recreate it in a new BP so it isn’t corrupted.
This is 4.7.3 on a mac.