Q: Getting an error when trying to download music from Family Sharing

Howdy mrscaskin,

Welcome to Apple Support Communities.

It sounds like you recently setup Family Sharing and are seeing an alert when trying to download a past purchase from the iTunes Store. The article linked below will explain the alert you’re seeing and provide information about using Apple IDs with multiple devices.

iTunes Store: Associating a device or computer to your Apple ID

When you turn on iTunes Match or Automatic Downloads, or when you download past purchases on an iOS device or computer, that device or computer becomes associated with your Apple ID. Your Apple ID can have up to 10 devices and computers (combined) associated with it, with a maximum of 5 computers at any time. Each computer must also be authorized using the same Apple ID. Once a device or computer is associated with your Apple ID, you cannot associate that device or computer with another Apple ID for 90 days. You can view which devices or computers are currently associated with your Apple ID, remove unused devices or computers, and view how many days remain before the devices or computers can be associated with a different Apple ID from the Account Information page in iTunes on your computer:

1. Open iTunes.
2. Sign in to your Apple ID by choosing Store > Sign In from the iTunes menu.
3. Choose Store > View My Account from the iTunes menu.
4. From the Account Information screen, click Manage Devices.

Next to each device or computer name, you will be able to see when each device or computer was associated with your Apple ID. You will also be able to track how many days remain before your associated devices or computers can be associated with a different Apple ID.

I hope this helps.

-Jason