Help Desk
Glenn Fleishman answers your most vexing Mac problems
WHAT TO DO WHEN TIME MACHINE SAYS A VERIFICATION FAILED
I’ve been a Time Machine sceptic for many years, even though I’ve used it at times, and have been writing about how to use it better and control it for that same length of time. That’s because Time Machine lacks much in the way of solving problems when things go wrong. Apple chose that approach for simplicity, but it leaves users in the lurch.
Take the case of Macworld reader Talon, who wrote in after they received a message (and not for the first time) noting: “Time Machine completed a verification of your backups on ‘Hobson’s Choice
Airport’. To improve reliability, Time Machine must create a new backup for you.”
This dialog presents two options: Start New Backup, which removes the entire existing backup history, and Back Up Later, which retains it but stops back ups. This is no real choice at all presented as a choice. Why did the backup become corrupt? Why can’t it be recovered? What is the meaning of life? We don’t know the answer to any of those questions, because Time Machine is impenetrable. With other backup systems, there’s usually a way to repair, recover, or extract files from a damaged backup.
Apple offers such an option without explaining it in the above dialog box – it’s in macos help, instead. If you pick Back Up Later, you can still try to retrieve files, by using the regular Time Machine interface. You may have no success, but it’s a possibility at least.
My advice as always is to have multiple backups of any file you want to make sure you have in the future – even if the future is an hour away or tomorrow. One copy is bound to fail, while two at least offer some peace of mind. Some phrase this as “3-2-1”: three copies of your data, two different methods, and one off-site.
WHY DOES APPLE ASK FOR YOUR PASSCODE WHEN SETTING UP TWOFACTOR AUTHENTICATION?
A Macworld reader who prefers to remain unidentified (since we’re talking about security
issues) wondered why Apple asked for his iphone passcode when he was setting up two-factor authentication (2FA).
I am a great supporter of 2FA as a way to deter the potential of ne’er-do-wells achieving access to your accounts through password breaches or other problems, since 2FA requires a physically present element in your possession (like your Mac or another IOS device) to confirm an account login.
However, our reader didn’t want to give up his passcode to Apple. What’s the point of having a secret passcode that protects your data and keeps criminals, governments, and nosy parkers out of your affairs if you simply hand it over?
The problem is that Apple is explaining poorly why they’re asking for your ios’s passcode. The company does everything in its power to never know your secret codes, and this case isn’t an exception. It’s just that Apple, in an effort at simplicity, doesn’t provide reassurance and documentation about what’s happening behind the scenes.
The dialog our reader sees reads as follows:
That certainly sounds as if Apple possesses the passcode after you enter it. However, the firm uses an encryption technique in which it makes use of the passcode only when it is entered on the device to encrypt the set of data described. It doesn’t retain the passcode in unencrypted form on the device ever – the passcode itself is stored only in a cryptographically transformed version in IOS devices’ Secure Enclave chips – and the passcode isn’t passed off your device to Apple. Instead, only the encrypted form of the data becomes available on other IOS devices. Using the same passcode on these other devices unlocks that encryption on those other devices. Apple never possesses the secret: only you do. You typically see this or a similar dialog only with icloud Keychain, which is the basis for a lot of user-access-only transfers of data via icloud.
The uniqueness of this request for one’s IOS passcode makes it seem different, and, without a lot of reassurance, it seems wrong.
Apple explains this in painstaking detail in a white paper, IOS Security, (tinyurl.com/yb28alsj) updated mostly recently in January 2018. But it could provide much less exotic warm feelings by stating: “Your passcode never leaves your device” or something similar. It doesn’t even mention the possibility of the above dialog box in its 2FA setup instructions (fave.co/2qvvbst), seemingly an oversight.
Never take it on trust what a company is doing with your data. That makes this undocumented and
under explained portion of 2FA setup unfortunate on Apple’s part, even if we can determine that it’s still adhering to its security and privacy philosophy.
HOW TIME MACHINE AND OTHER BACKUPS HANDLE EMAIL
After several recent columns on the vagaries of managing Time Machine backups, including how to prune snapshots and ensure you don’t delete files from the backups you want to keep, Macworld reader Janet wrote in asking about how Time Machine interacts with email.
She wondered how Time Machine creates a backup of email messages, given that Mail stores these messages in what appears to be a file or database format. And what happens if you delete an email message months ago and want to retrieve it?
Looks can be deceiving: while mailboxes look monolithic, Apple stores each message and attachment discretely, which is in part to allow Spotlight indexing and per-message backups.
You can see how messages are organized in ~/ Library/mail/v5/ and expanding down into any folder that has a name with a combination of letters, numbers, and hyphens.
To find an old email message that was deleted from a Time Machine archive, you open Mail, enter Time Machine, and scroll back to the date at which you believe the email last existed. Then you can find it in the appropriate mailbox.
While other local and cloud backup software, such as Arq, Backblaze, Chronosync, Spideroak, and Crashplan, also back up these individual mail message files, there’s no good way to load or retrieve just deleted messages you want to retrieve – they’re much harder to find, and you’ll most likely pull up an entire old mailbox and then import it into mail to look through.
Deleting messages accidentally is, of course, something you can’t avoid. But I recommend being more intentional about email. Most of use server-
side email (IMAP), which lets you retain messages on your mail server but gain access to locally cached copies on any computer or mobile device. For messages I want to be sure to keep, and not be dependent on a server to retrieve later, I drag them on my main Mac to a folder in the On My Mac section of the Mail navigation toolbar. Then these messages are not only local and persistent, but easier to identify later as important.
Once you move a message in this fashion, it’s no longer on your server account, so it will only be available from the Mac to which you copied it, but that’s often exactly what you want for older messages you need to retain.
WHAT HAPPENED TO THE ‘ALL MY FILES’ FEATURE IN HIGH SIERRA?
Macos’s All My Files option in the Finder is a great example of a feature that you barely know is there until it disappears. All My Files was a default feature of the Sidebar that, when selected or shown when opening a new Finder window, listed every file created on your Mac in reverse chronological order.
It disappeared in High Sierra, replaced by a Recents item. Many people searched around for it for some time, including yours truly. Macworld reader Ralph thought he accidentally deleted All My Files, and is trying to restore it. Unfortunately, it’s gone and Recents simply isn’t as good.
Recents would also seem to show recently changed files, but in practice I find it’s pulling from a smaller set of locations, and, based on my
experience with two Macs, it’s often weirdly not up to date and missing changes. There’s no way to customize it.
While you can create Smart Folders in the Finder that have complicated stored Spotlight searches, Apple has barely touched Spotlight search parameters for years. There’s no way to do a search as simple as ‘all files, chronologically reversed’.
It’s unclear why Apple removed All My Files. I had no complaints, and I can’t imagine it was confusing to users, because it did exactly what it said on the tin: showed all my files.