If you purchased any music from iTunes between 2003 and 2009, you downloaded tracks with digital rights management (DRM) embedded in them, which means you can't easily transfer them. Apple has since stopped using DRM, but old files may still include it. Wired shows how to update your music library with the new, DRM-free versions.
The process here is pretty simple, but if you're anything like me, you never bothered to actually do it:
- In iTunes, select iTunes > Preferences and click the "Store tab"
- Make sure "Show iTunes in the Cloud Purchases" is checked and close the Preferences panel
- Click on the cloud icon in your list view and make sure all your purchases are there
- Now, delete the old DRM versions by sorting by "Kind" in the list view (if it's not there, go to View > Show View Options and select it)
- Scroll down to see if any tracks are listed as "Protected AAC audio file." That's the DRM music you need to replace
Once you run through the process of deleting those songs you can download them from the cloud at any point, DRM-free. This has been around for a while, but if you haven't grabbed those DRM-free versions, now is as good a time as any.