This week I look into two people sharing one Apple ID, one person wanting two, and two people splitting their one account in twain. Also, something's up with an over-alert Mac on a couple's network--what could it be
Shared accounts
Gil Ceniceros asks a question that's quite common:
My partner and both share the same iTunes account, and my question is how do I fix the following. When home and someone calls my phone, their phone rings as well. Also when I'm on a webpage, it shows on their phone as well, or email. How do I turn these features off so we are not getting each others info or have the info synced
This is a tricky one, because an iTunes account is effectively always an Apple ID as well, which can be used with iCloud and other services as well. If the same account is an iCloud login, then all the messaging and Handoff features--showing pages accessed by Safari on any device, etc.--are available on every computer logged into the same Apple ID with iCloud unless you disable a slew of features. It sounds as if Gil and his partner use their ID that way.
You can control Messages in iOS and OS X well enough to choose what notifications appear on which devices. In OS X, switch to Messages and choose Messages > Preferences. Click the Accounts icon and then the iMessage item, which is labeled with your iCloud login. In that dialog, you can opt on each OS X device for which emails and phone numbers you want to receive notifications.
Use Settings > Messages > Send & Receive to reach the same toggles in iOS. In Settings > Messages, you can also tap Text Message Forwarding to decide which Macs receive SMS and MMS messages.
You can also control whether a given Mac receives iPhone cellular calls (though not for which phone numbers) and incoming FaceTime sessions, whether audio or video, from the OS X FaceTime app (FaceTime > Preferences > Settings) or in iOS (Settings > FaceTime). iOS lets you disable all iPhone Cellular Calls with a switch in that same settings area.
(Carlos A. Mason wrote with a tangential question: His late 2012 MacBook Air can't handle an incoming cellular call over FaceTime quickly enough to answer it! I had the same problem with my 2011 Mac mini and 2011 MacBook Air. Unfortunately, this seems to be some kind of system limitation, as there's no workaround or system optimization you can do, even when the feature appears to be working.)
iOS also lets you disable Handoff in Settings > General > Handoff & Suggested Apps, while OS X hides it in System Preferences > General, at the bottom. Handoff can't be used selectively as with Messages, so it's all or nothing. Gil or his partner could choose to enable Handoff just among one or the other sets of their devices, but then the other person wouldn't also be able to use it.
Long term, the best thing is to have separate Apple IDs, but that would work well only if Apple's Family Sharing were more robust in how it allowed music, apps, and media to be used across multiple accounts. We assume that will continue to improve over time, or Apple will revamp its account system entirely. (We can hope, can't we)
Apple ID email re-use and family trouble
Leslie Sakolnik wrote with a variant on a different, but related Apple ID problem:
Previously when I needed to, I used my personal Apple ID at work. Now I want to create an Apple ID for work. I tried to do so and got a "this email is associated with another Apple ID" error. I did have my work address set as a recovery email and deleted that, but am still unable to set up an account.
Apple is very persnickety about email addresses and Apple ID accounts. Once you've used an email address with one Apple ID, even if, as in Leslie's case, she deleted it as a backup address from that account, it's likely impossible to ever use it as the primary email for another Apple ID. You often can set it as a backup address for a different account.
Reader Daryl Balfour tried to transition his wife and he from one Apple ID to two and rely on Family Sharing, and had something similar occur. After updating their Macs and iPad to the latest versions of iOS and OS X, he tried to set up Family Sharing, but...
...every device tells me that I can't do that as my Apple ID email address "is already used for shared purchases" in my wife's family, and that I should ask her to send an invitation to join Family Sharing.
However, his wife never set up Family Sharing, and every one of their devices shows Set Up Family Sharing in iCloud. One of them should be marked as the organizing system, but none of them actually is.
This seems like deep arcana on Apple's side, and if it can be fixed, it has to be fixed by Apple, as there's nothing you've missed in the process--unless there's a secret Apple device lurking your house that's somehow set itself up as boss. Get in touch with iCloud support and see what they say.
Mystery wake
Hank Hofmann has a curiosity:
My wife and I each have an iMac (hers is a mid-2007 model and mine is a mid-2009 model). Both are on the same home network and both run the same version of Mavericks. When we are not using them, both are in Sleep mode. Frequently, when I start a new session out of sleep mode on my iMac, after a few minutes her iMac will suddenly turn on by itself (but the screen stays dark). But the reverse never happens; that is, when she starts a new session out of sleep mode on her iMac, it never results in my iMac turning on by itself (with the screen dark). I'm just curious as to why this might be. Any ideas
It's very likely an oddity related to Wake on Demand and Bonjour Sleep Proxy. These aren't controllable features per se, but built into OS X and aided by other Apple hardware. They allow a Mac to continue to interact in a background manner when they are ostensibly asleep, without fully revving up. (For an NSFW look at problems caused in Yosemite with Bonjour Sleep Proxy--I can't even reproduce the title here--read The Icon Factory's Craig Hockenberry's account. The TL;DR is that for strange Wi-Fi disconnects and high CPU usage, you might need to restart all your Apple TVs.)
My suspicion is that a slight difference in configuration or available shared services between the two machines is the cause. Perhaps your wife's machine has iPhoto Sharing enabled, or Back to My Mac, and yours does not
This may explain why things wake in the night. The only way to prevent this would be to figure out precisely what your wife's iMac is advertising on the network and disable those services. The free Bonjour Browser (old, but still functional in Yosemite) offers a nice organized glimpse at what's on your local network. (The app isn't signed, so after copying it into Applications, Control-click the icon, select Open, and then click Open in the warning dialog box.)
Ask Mac 911
We're always looking for problems to solve! Email us at mac911@macworld.com or tweet them at me (if brief) @glennf. Mac 911 can't provide direct email responses or answers for every question. For that, turn to AppleCare, an Apple Store Genius bar, or the Apple Support Communities.