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"Enter your passcode to trust this computer and start a backup." Every time iPhone is on charge.

After the upgrade to iOS 16.1 from iOS 15.7, with no other changes to my paired iMac, my iPhones now both routinely ask me to type in my passcode to trust this computer and start a backup. This happens whenever the device is put on charge, even if only to AC power, and the sync and backup happens over Wi-Fi. Why, and how do I put a stop to it so it goes back to the iOS 15 and expected behaviour of doing the sync and backup over Wi-Fi automatically and immediately when the device is put on charge?


I've looked around and tried various solutions, all to nothing. I reset privacy and network settings, repaired over USB, restarted everything, etc. It's still happening.

iPhone 13 Pro Max, iOS 16

Posted on Oct 31, 2022 2:20 PM

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Question marked as Top-ranking reply

Posted on Nov 3, 2022 9:59 AM

Upgrade to 15.7.1 or 16.1 causes the iPhone, iPadMini and iPad to require entering a pass code EVERY TIME to do a backup to Windows iTunes 12.12.6.1 The automatic backups are broken. Prior versions only required a one time entry of the pass code to trust the device (PC running iTunes) and then would resume automatic backups after a software upgrade.

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158 replies

Dec 1, 2022 8:50 AM in response to StMiBa

StMiBa wrote:

By Apple providing a means for users to do one of three things: Require a passcode for each backup, Require a passcode for the devices to trust each other permanently or never require a passcode.

In other words, we should be able to opt-out of these draconian decisions made in the name of our safety.

Until your phone was hacked; then you would probably sue Apple. So protecting you is also protecting Apple.

Dec 1, 2022 8:50 AM in response to StMiBa

Maybe you should move on if that is what you feel would make you happy.

I will stay in a secure ecosystem.

The same argument applies to 2 factor authentication. It is mandated by Apple but you can move on out of the ecosystem if you object.

Used values of iphones and Macs are pretty high due to popular demand. Sell it all. Free your spirit.

Dec 1, 2022 10:59 AM in response to StMiBa

Lawrence, you pointing to that hack doesn’t justify this change, since as was mentioned multiple times, that hack doesn’t apply to people with encrypted backups. So I suggest not posting that as a blank check justification in response to every (justified) complaint about this issue. It doesn’t make sense.


LD150, if you want a “secure system”, I hope you’re not using Apple’s iCloud Backup instead, which Apple continues to offer despite it not being end-to-end encrypted (on purpose to allow governments to access your private data on demand). Local backups are much more secure than iCloud because they are encrypted. Again, this has been pointed out multiple times, so no need to reply to every new comment with old arguments that don’t apply. All it does is increase your post count.


StMiBa, honestly, this feels like a flick of the wrist, clumsy, ad hoc hole-filling by Apple. I haven’t yet given up the hope that they will come up with a better solution (like an exception to this for encrypted local backups, or forced encryption on all local backups). I hope I’m not proved wrong.

Dec 1, 2022 11:06 AM in response to DollaDollaBillsYall

DollaDollaBillsYall wrote:

Lawrence, you pointing to that hack doesn’t justify this change, since as was mentioned multiple times, that hack doesn’t apply to people with encrypted backups.

As has been pointed out it DOES apply to encrypted backups, because if a hacker can download the encrypted backup to their computer, since there is no limit to the number of “guesses” for the passcode they can create a script to try every possible passcode, the same way passcodes are hacked in data downloaded from hacked websites.

Dec 1, 2022 1:59 PM in response to Lawrence Finch

Are you saying that in order for my personal data to be secure, I should delete the backup that is currently stored on my Macbook? Is that seriously what you are saying?


If that's the case, why should I bother to backup my data?


What I hear you saying is, "I have no idea what the problem is or how to fix it and neither does Apple but Apple assures me that if I enter my passcode in order to initiate a new backup, I'm secure."

Dec 1, 2022 2:31 PM in response to StMiBa


StMiBa wrote:

Are you saying that in order for my personal data to be secure, I should delete the backup that is currently stored on my Macbook? Is that seriously what you are saying?

If that's the case, why should I bother to backup my data?

What I hear you saying is, "I have no idea what the problem is or how to fix it and neither does Apple but Apple assures me that if I enter my passcode in order to initiate a new backup, I'm secure."

It’s clear that you haven’t read the thread. Your iOS backup is saved in protected storage on your Mac or PC that only you can access. The security vulnerability allows a hacker to create a new backup of your device in storage that is not protected, then download the backup to their computer to analyze. They could do this for any device that just once “trusted” the computer. Apple has blocked this vulnerability by requiring a passcode on the phone each time it is backed up. I suspect this is a temporary fix for this vulnerability until they can find a better one. If it was just hypothetical I doubt Apple would have rushed out this fix, but the code to perform this hack has been published for anyone to see. There’s even a link to it in this thread if you want to try it.

Dec 4, 2022 5:18 AM in response to Lawrence Finch

Lawrence Finch wrote:


DollaDollaBillsYall wrote:

Lawrence, you pointing to that hack doesn’t justify this change, since as was mentioned multiple times, that hack doesn’t apply to people with encrypted backups.
As has been pointed out it DOES apply to encrypted backups, because if a hacker can download the encrypted backup to their computer, since there is no limit to the number of “guesses” for the passcode they can create a script to try every possible passcode, the same way passcodes are hacked in data downloaded from hacked websites.


Although true in theory, this is incredible in practice. Encryption for iOS backups use (at least) AES 128, with PBKDF2 with 10,000 rounds. Such a password would take billions of years to crack. When a website is compromised, it's almost always easier to simply compromise the data; as long as the site is competently implemented, it will use similar key strengths with password stretching, and probably even better algorithms now (it's the key case for "passkeys", of course, to abolish passwords altogether and simply use keys). Straightforward cracking of password hashes is less and less useful as people refrain from reusing passwords or using trivially weak passwords, so while breaches do still happen, it's not chiefly due to the cracking of passwords that they are a concern. Seriously -- this idea that a single, small fish in a vast pond would be worthy of such cracking effort is beyond silly, and the idea that protecting a backup by prompting for a passcode every time is justified for that reason is risible. Protecting the backup on the Mac, in the absence of on-disk encryption, is merely added protection whilst the system is booted; it doesn't really add any security, but is at best defence-in-depth, and the most charitable interpretation for the change is simply that Apple is extending a completely unnecessary protection to Windows users that Mac users enjoyed (very recently) from OS changes that enforce sandbox restrictions, albeit, as discussed, without any regard for the purpose of automated backups. This change is therefore policy, not security.


BTW, iOS 16.1.2 doesn't fix this issue, of course.

Dec 7, 2022 8:29 PM in response to Lawrence Finch

Well, Apple's security team makes mistakes, you know. Remember Goto Fail? Dearie me.


And while I think they're largely competent, if subject to the usual commercial pressures that lead any profit-seeking corporation astray, I don't think they're above the many cryptographers and other cybersecurity people who use the primitives Apple are using for backup. They are strong, and hard to break. Maybe you don't believe that; in that case, give thought to opting out of the digital world, because you have no security. :)


I have said that I think this is policy. I still think so. I realise that not everyone is affected, but this is clearly noticeable for many long-time users. For starters look at the Me Toos on this topic. It is obviously a problem for many to use iCloud, whatever you believe Apple's motives are; it is objectively less secure. I am frankly astonished that this is mostly not talked about elsewhere, but it probably speaks to the fact that iOS devices are now "post-PC" in every sense. A triumph, to be sure. Let's hope most iPhone users left iCloud Backup on at the default, and paid for storage when they ran out instead of just turning it off. Otherwise they'll be in trouble if disaster strikes.

Dec 8, 2022 7:20 AM in response to sgucukoglu

As to economic arguments, what does storage cost on your computer? A computer backup uses a lot of storage; one backup of my phone is 25 GB, and that’s when I’m syncing photos to iCloud. For fast SSD internal storage in your computer (similar to what a modern Mac has) is about $1 per GB. So each of my computer backups is using $25 worth of my storage. If I didn’t sync photos to iCloud that would make the backup about 20 GB larger, so my cost would be $45 per backup. That same backup to iCloud would cost 99¢ per month or $12 per year.

Dec 8, 2022 3:47 PM in response to Lawrence Finch

They didn't fix the vulnerability, they stopped automatic unattended backups. The vulnerability still exists.


The vulnerability ,simply put, is that someone could direct the backup (time machine) to store its data in an unprotected area of the hard drive. They should have changed to OS to prevent someone from changing the location of the backup.

Dec 8, 2022 5:01 PM in response to StMiBa

StMiBa wrote:

They didn't fix the vulnerability, they stopped automatic unattended backups. The vulnerability still exists.

The vulnerability ,simply put, is that someone could direct the backup (time machine) to store its data in an unprotected area of the hard drive. They should have changed to OS to prevent someone from changing the location of the backup.


The vulnerability no longer exists because you must physically enter a passcode on the phone to back it up each time. So there is no way for someone who hacks into the computer to change the storage location of the backup, which is hard-programmed into iTunes (or Finder).

Dec 8, 2022 5:23 PM in response to Lawrence Finch

That’s false. The backup location is easily changeable using a symlink. Having a passcode prompt does nothing to prevent this. The fact that you can change the backup location is a good thing because it lets you store your phone backups on an external drive instead of taking up half of the miserly amount of storage Apple provides in their laptops and charges an arm and a leg for.

Dec 8, 2022 5:28 PM in response to DollaDollaBillsYall

No, that won’t work. Only the administrator account can add a symbolic link to replace the correct backup location, as the enclosing directory is both hidden and is “owned” by iTunes, the same reason a hacker cannot download a backup you create with iTunes from the default backup location. Do you honestly believe that Apple’s cybersecurity team doesn’t know what it is doing, and you do?



"Enter your passcode to trust this computer and start a backup." Every time iPhone is on charge.

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