Hi Baronvonblack,
Thanks for using the Apple Support Communities! I understand that you're unable to open the Help menu in Garageband 10 because you're getting a message that says 'info unavailable'. Having access to the Help files is a handy feature whenever you're working on a project and I'm happy to offer some suggestions to help you.
The first step I would recommend to try is starting up in safe mode and then test out the Help menu. If the issue doesn't happen in safe mode, then there may be an issue with your log in items. You'll find the steps for this here:
Try safe mode if your Mac doesn't finish starting up
Another step that you can try is to test this issue in another user account on your Mac. This will let you know if the issue is related to any system or user files that are specific to your user account.
How to test an issue in another user account on your Mac - Apple Support
Cheers!