Hi there, kaili228.
You mentioned restarting and safe mode. To clarify, did you restart your Mac and then put the Mac into safe mode? We want to ensure we understand the steps taken already with your Mac and GarageBand.
If you haven't done the steps mentioned above, you could see if those can help resolve the issue, as both help with software issues. If it doesn't resolve the issue, it can at least help isolate what might be going on:
If you've already done those steps, you can try to help isolate this issue further by logging into your Mac in a new (if needed, temporary new) Administrator user: Set up users, guests, and groups on Mac - Apple Support A new user doesn't have custom or changed settings, and can help determine if the issue is within your specific user or not.
Take care!