Garage band won't launch on my macbook pro

When I try and launch the program it says that it needs to download samples and loops, and that it might take up to an hour. But about 90 seconds later I get this message: GarageBand was not able to install the new sounds. Close and re-open GarageBand to download and install them again."

So I've tried to close and reopen it several times, and it just takes me to the same dead end. I've uninstalled and reinstalled the app, but that didn't change things either. The App store says I have no updates needed. I did the latest GarageBand update within the last month but haven't tried to use the program until now.

This program is useless to me right now because I can't even open it!