GarageBand 10.0.3 error "Could not find layout General Audio 10" when choosing vocal patch

Same problem here!

I posted this under a different topic as well but the following process fixed the issue you described and some others:

I was having the same problem but I selected the "Garageband" drop down while I had a project open and selected both "Restore Sound Library" and then "Update Sound Library" and after those were complete I'm good to go!

Chevontez wrote:

I selected the "Garageband" drop down

So confusing... I'm like, "Where the heck is the "Garageband drop down"? We in the mac world (and PC, too, I believe) refer to this (I figured out) AS A MENU! "Drop down menus are entirely different!