Why is my Tuner button in Garageband 10.0.2 greyed out ?
Why is my Tuner button in Garageband 10.0.2 greyed out ?
MacBook Pro, OS X Mavericks (10.9.2)
To use the Tuner, you need to have a real audio track selected, and an input device.
Check, the input in the Info panel for the selected track does not show "No input". Then you should be able to open the tuner, even if it should still be grayed out.
You can select an input device in the GarageBand preferences Audio/Midi tab.