Apple’s servers still serve the correct legacy packages for El Capitan. If the download fails, quit GarageBand, delete ~/Library/Application Support/GarageBand/ (temporarily), and restart.
: If GarageBand is not in your purchase history, sign in with your Apple ID on a newer Mac that supports the current GarageBand. "Buy" the free app there so it links to your account. Then, return to your El Capitan Mac and use the Purchased tab method described above. garageband mac os x el capitan 10116 download extra updated
: If you already have GarageBand 6 but need the sounds, Apple still hosts Legacy Content Packages for GarageBand 6 basic content. How i can download an old version of Garageband Apple’s servers still serve the correct legacy packages