Error messge: Generation has thrown an exception: list index out of range when wanting to generate rig i know this question was asked before but there was never an answer. I used a human meta-rig and wanted to use generate rig. But no mater what I do the error message: 

Generation has thrown an exception: list index out of range 
apears.

Does anyone know how to fix the issue?
My best guess: you tried to partially delete the face.
Unfortunately you can't selectively delete parts of the face (as of 2.82a, later versions may provide more flexibility). 
Either keep the whole face or delete all bones that belong to it.  

Some info may be found here:
https://developer.blender.org/T53842