Question: MultiUser iTunes: iPhone + MacOS + AppleID

How can I use one Mac as the backup and AppleID server for two users?

Each user has a separate iPhone, MacOS login, iTunes library, and AppleID. The Mac is shared for reasons of backup (TimeMachine) and having a big screen to manage the library. Both libraries include Apple purchased content and other content from other sources, including some that are completely not recognized by Apple Music (personal recordings, rips from vinyl, rips from tape, etc.). The way I expected to use it was "log in as UserX, open UserX's iTunes library, do some users-itunesy stuffs."

I thought I had this working, but lately (possibly since Mojave+iOS 12.0) I'm getting:

User uploaded file

"90 - 61 days ago" could be about when I first set up this two-user configuration.

Mac mini, macOS Mojave (10.14), or whatever's the latest

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Oct 12, 2018 9:41 AM in response to Jack Repenning In response to Jack Repenning

You should be able to make new purchases from either of two Apple IDs with such a set up, and possibly download them immediately. Downloading past purchases from either account is going to cause you problems however. Apple really want you to stick to one Apple ID per device. Family Sharing might provide a workaround.

Authorization vs. association

Up to 5 computers can be simultaneously authorized for each Apple ID. There is no direct record of which machines are authorized. It is up to you to keep track. (I use a small text file in my main iTunes folder.) iPods & iOS devices are limited to DRM protected content from up to 5 different accounts. There is no limit to the number of devices that you can load up with content using iTunes. You can deauthorize computers that you no longer wish to use to access protected content so that you can authorize others. You either do this on the specific machine or deauthorize all and then reauthorize as needed. Having used deathorize all you cannot use it again for a year, though Apple Support may be able to perform a reset if you can explain why you need to reuse the feature before it becomes available to you. Reinstalling Windows without deauthorizing first will use up an authorization.

HT201251: Authorize your computer in iTunes - Apple Support

A mix of up to 10 computers and iOS devices (no more than 5 computers) can be associated with your Apple ID for iTunes Match/Apple Music, automatic downloads, or redownloads of past purchases. There is a 90 day limit before a computer or device can be switched to another ID or the association removed. The list of associated devices is the one you can see within your account details in iTunes. You associate a device or computer by using certain features, typically downloading past purchases. You don't necessarily need to associate a computer or device with your Apple ID to use it with your content. Again Apple Support may be able to reset if you can explain why you need to reset the association early.

HT204074: View and remove your associated devices in iTunes - Apple Support

You can happily remove any and all associations that are not within the 90 day limit. Those that you actually use will be recreated as and when you make use of a service that triggers association.


Oct 12, 2018 9:41 AM

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Oct 12, 2018 11:41 AM in response to turingtest2 In response to turingtest2

OK, I think that explains everything I'm seeing. But man is it complicated! It looks like at least five minds were involved in the "design," and zero coordination. I'm going to have to take a few days to game-play through all that to figure out how to work, both how to dig out from my current mess and how to work in the future to avoid new lock-outs.

Not checking either "Helpful" or "This solved my question," as this fine and clear response only gets me to a more accurate appreciation of the unholy mess I'm in. Thanks, tutingtest2, for your fine work explaining the swamp.

Oct 12, 2018 11:41 AM

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User profile for user: Jack Repenning

Question: MultiUser iTunes: iPhone + MacOS + AppleID