GarageBand Help with Loops and Plug-Ins

Greetings,

Boy, I wish i knew what the answer was to this:

I received the new GarageBand (10.1.2) in the OS expression of all our new Macs. To get a complete feel for the app, I also purchased MainStage 3 and, like most all instructions indicate, used that app to download (and in effect, re-claim) all of the JamPack Loops that one could get. Boy, it took a while, but in the end I had all available sounds.

Or so i thought... launching GarageBand, to my chagrin, it indicated that there was yet still more content available for download (some 9 GB worth). This was done - after re-indexing the loop library, I thought finally I was good to go.

Not so...

Every loop, clearly indicated in the loop library AND clearly previewed by clicking on it, that I attempt to drag into the session comes back with an error message, which goes like this:

EXS24 instrument "African Kit.exs" not found.

or

EXS instrument "Peruvian Pipes.exs" not found. (replace the instrument name with whatever, but the end result is the same). Doing a search in the library (the left side of the screen) produces no results.

Any idea of what to do? The fellow at Apple tech support said that this was a new one on him. Did i download 50 GB of nothing? Does anyone know (definitively) where all the loops/instruments/samples that MainStage and GB downloaded are, and is there any way of successfully tagging them so that GB recognizes them?

Thank you for your consideration; this supposedly easy app is certainly more perplexing than it needs to be :-\

Regards,

D Collins