Hello nobel256,
Welcome to Apple Support Communities. Try these steps to help with this GarageBand trouble:
Reset GarageBand preferences
Resetting preferences doesn't affect your project files, presets, or patches. However, you do lose any custom preference settings you might have made.
1. Choose GarageBand > Preferences, and note any specific preference settings you've made.
2. Close GarageBand.
3. In the Finder, choose Utilities from the Go menu.
4. Open Terminal.
5. Copy this command, paste it into Terminal, then press Return:
Further steps can be found in the Apple Support article:
If GarageBand isn't working on your Mac - Apple Support
Feel free to reach back out if you have any questions.
We hope this helps you.