. Its a light grey colour.
What is a light grey color? The "Download More Sounds" from the GarageBand menu? Is the "Restore Purchase" option active? Then try that option.
Are you signed into the App Store with the same Apple ID you used to upgrade to GarageBand 10.0? Check the "Store" menu in the App Store app, if you are signed in. And check the "Purchased" tab of the AppStore, if you need to "Accept" GarageBand.