If you ever update your OS, you must delete this old GarageBand and install the new 300+ MB version (which requires 2GB+ of sounds). Did this work for you? Let me know in the comments.
If you are still running and need to install GarageBand, you cannot simply download the latest version from the App Store—your Mac won't recognize it. Garageband Mac Os X El Capitan 10.11.6 Download
Apple no longer supports El Capitan. The current version of GarageBand requires macOS Ventura or later. To get a compatible version, you must download the last compatible release . Title: How to Download GarageBand for Mac OS X El Capitan (10.11.6) Last updated: [Current Date] If you ever update your OS, you must