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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

Nov 13, 2022 5:39 PM in response to DollaDollaBillsYall

Thanks for that. Now, if only Google were good enough to find that thread. Very, very unfortunate, and I think that's clearly and obviously incorrect behaviour. I'll contact Apple Support to confirm as well, but it looks pretty solid. It's also deeply insidious that you can't turn backups off; the choice is between leaving them on and getting prompted to enter your passcode, or leaving them on and using iCloud, for which there is in all probability a fee for most users. Perhaps all those not seeing this should check if they're using iCloud for backups, since the only other explanation is that they aren't syncing. And let's be honest, the intersection of users still using both local backups and sync is probably small enough that this issue just hasn't received that much attention.

Nov 15, 2022 12:55 AM in response to LD150

Then shouldn't this "feature" be turned off after a single trust for Macs that have FileVault on? Unless Apple has been skimping on security for their consumer computers. Plus this change doesn't do anything new to prevent local backup data from a computer from being synced TO an iPhone. It doesn't even add any new encryption to an iPhone backup on a computer, which was already encrypted at another layer on top of FileVault. A thief would require all 3: your computer passcode, your FileVault key, and your iPhone encrypted backup password. This only adds the mere appearance of security by requiring a passcode entry that doesn't actually encrypt anything.

Nov 15, 2022 3:45 AM in response to DollaDollaBillsYall

In my consumer opinion, it is an update that just cause inconvenience. Apple, please reverese that or allow to modify it in the setings or with the face ID. This update does not change the encryption, it just limit the users who regularly backup phones in their PCs. Sometimes IOS updates bring innovation, but more than often afects a product that was working fine. I wonder how is this feature in droid telephones?

Nov 15, 2022 7:38 PM in response to DollaDollaBillsYall

The backup process, including encryption, is entirely under the control of iOS. I'm just not seeing a plausible explanation for why you'd need to go out of your way to protect an encrypted backup, exported directly from a device, any more than it already is. Maybe they don't trust users to set good passphrases? Or the encryption is known to be weak somehow? Or they're just paranoid of TLAs?


And speaking of spooks, remember that iCloud Backups, while they don't hold the same data, and hold only device-specific encrypted data, are nevertheless accessible to Apple. So I'm not sure it's possible to trust iCloud more than your local backups anyway, unless of course you don't think privacy is important when it's from spooks ...


I chatted with Apple Support. They hadn't heard of this issue, but, having searched, can't find anything indicating that this is a feature rather than a bug. They've "fed back" for me. You might send your own, too, and we can try and get a resolution to this.

Nov 15, 2022 9:04 PM in response to sgucukoglu

What's interesting is that after the backup, if you disconnect the phone, and a few minutes later reconnect it, as always, it begins to back it up again. And, again asks for the password, which makes no sense because the same phone is connecting to the same computer...and they both know that. So in the end, it looks like this problem is a bug.


And just for fun, as an odd fact that many don't know: we use the term "bug" because, way back when lots of equipment used relay logic, the relays at the time weren't sealed. So, a bug sometimes got into the machine and was sitting between a contact pair when the relay energized, mashing the bug and preventing contact. In time, it became a joke. When a problem showed up the tech would laugh and say, "Time to debug the machine." The term stuck, and is still in use, though few know why.

Nov 19, 2022 11:44 AM in response to sgucukoglu

The big problem I have with this is that I back up several iDevices for family to a Windows machine. The idea being they’re at home, they plug in to a charger, the device backs up without them knowing or thinking about it.


Now with this behavior, every time they plug their phone to the charger, they get an unexpected popup asking for their password. They are trained NOT to enter in their password at random, unexpected prompts. So of course they deny it and the backup does not take place.


And further, we all use complicated alphanumeric passwords (to thwart GrayKey style attacks) so it’s a bit of a pain to constantly type in a 20-letter alphanumeric password with mixed case.


I’m sure Apple would love to nudge people towards one of their paid iCloud plans (and I actually have one, but not for device backups) but I won’t use iCloud for device backups until Apple implements end-to-end encryption, which they currently do not. iCloud backups (and iOS vulnerabilities) are the only way the government or malicious actors can get at your data due to the lack of E2EE.


This isn’t surprising though, I have noticed over the years that iTunes seems to be a neglected piece of software with bugs and glitches, but it has been a reliable platform for device backups. Until now.


So yeah, I definitely have submitted feedback through the suggested channels but am pessimistic this gets fixed.

Nov 19, 2022 12:37 PM in response to dmdx86

Well, you are wrong. Data between your device and iCloud is end to end encrypted. Actually, ALL data in and out of an iOS device is end to end encrypted. And iCloud itself is encrypted in storage. The vulnerability is that your Apple ID and password is the encryption key, so it is essential to protect them and use 2 factor authentication.


But it can still be more secure than your computer, which can be stolen or seized by law enforcement.


I wonder about why some setups request the iPhone passcode. Mine doesn’t for any of my 4 iOS devices, so what makes it different? And all of them back up automatically. All on iOS 16.

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

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