My grand piano in Garage band is sharp, on every note.

Hi there, edwardem.

I see that the pitch is a little sharp when using the Grand Piano in Garageband on your Mac. I'm glad to help with this.

Correct the pitch of regions on an audio track -- See if this section of GarageBand Help corrects the issue.

Let me know how that goes, and take care!

Thanks for getting back to us, edwardem. It's appreciated. At this point I'd like you to contact Apple Support for further help with this issue.

Apple - Support - Product Selection — After selecting this link, choose Music, Apps & Services > Mac apps > Garageband > Issue with built-in audio. Then select how you'd like to start the conversation.

Cheers!