Update: That didn’t take long! Apple has just released an update for GarageBand on the Mac that officially adds support for iPad projects. It’s 181MB and seems to include add all the software instruments found in the iPad version that were missing
So ignore the workaround below, update GarageBand and you’ll be all set.
At the time of writing (March 2011), the Mac version of GarageBand can’t open files created with the iPad version. Instead, you’ll get an error message and the file won’t open. This is presumably because the iPad version has some features, instruments and loops not yet available in the Mac version.
Apple has promised an update, but for the time being, I’ve found this workaround.
Before you try this, let me stress that it’s a workaround with issues: your files won’t open perfectly, but at least you’ll be able to get some of your project onto your Mac. However, please do make sure you make a copy of your project file first.
First, copy the project file onto your Mac with iTunes. Then, right-click the project file and choose “show Package contents”. Find the “projectdata” file and open it, preferably with the Plist Editor, but a plain-text editor should work as well in a pinch.
Now, when you open it with GarageBand, you’ll receive a warning (as opposed to the earlier ‘error’ message), but you should be able to open the file, albeit with some errors and warnings.
Note: There’s a reason Apple changed the version number and you’ll find a lot of things won’t work (e.g. certain Apple Loops and instruments will be missing – note the empty drum track in my screenshot). But if you just want to get the basic project information and the bits you played off your iPad onto your Mac, it’s worth a shot.
Presumably Apple will soon be releasing an update for GarageBand on the Mac, so hopefully this hacky workaround won’t be necessary much longer. If you’re reading this long after March 2011, make sure you have all GarageBand updates first.