When you connect your iPhone, iPad, or iPod touch via USB cable to a Mac or PC for the first time, a prompt pops up asking you to trust the computer. The same prompt appears when another device is attempting to access the files of your iOS device for the first time or just periodically as a safety measure.
In this tutorial, we’re going to cover everything related to the ‘Trust This Computer?‘ popup and show you how to untrust computers & devices you trusted earlier on your iPhone or iPad.
What’s a trusted device?
A trusted device can access the files and settings of your iOS device, create backups, import photos, access movies & videos, contacts, and other items. The data stored on your iOS device isn’t exposed before you enter your passcode, if any, and choose to trust the connected computer or device.
If you choose not to trust the connected computer, you will still be able to charge your device through a USB cable, but the computer won’t be permitted to access any content on your iPhone or iPad.
So, when you connect your iPhone to a computer or a device to your iPhone’s Lightning port, the alert is essentially telling you that you’ve connected your device to an unknown computer that it’s never been connected to before.
Apple introduced this feature in iOS as a sort of chain of trust to prevent outside machines (both computers and peripherals) from easily getting access to your data. The owner of the device needs to express trust for the machine by tapping the Trust button before iOS communicates with it. If the Don’t Trust button is tapped, then the device will not communicate with the computer it’s plugged into.
When you trust a machine, a special key is saved on both the machine and the iOS device you are establishing a chain of trust on. If the keys match, iOS allows a secure transfer of information between the machine and the device; but when they don’t match, iOS is designed to keep your information safeguarded.
Before a computer can be trusted, you must first unlock the device with its passcode. This is the first step in security to ensure that only the device’s owner can express permission for the device to be used with the machine. Once in, the user of the device can plug it into a Mac or a PC for the first time, and the alert will appear.
The alert will not reappear for machines that have already been trusted, but if you recently chose not to trust a machine and you unplug and plug the device back in again, the alert will reappear, giving you the option to either Trust or Don’t Trust the computer again. If unused for a period longer than six months, you may experience a chain of trust expiration, and the trust will have to be reestablished once again.
When to untrust a computer
Some of the situations that might warrant untrusting a Mac or Windows PC from your iPhone or iPad include:
- You accidentally trusted a computer: If you accidentally trusted a computer, untrust it using the above tricks.
- You trusted a friend’s computer: If I’m transferring a friend’s media over to my iPhone and the file is too large, I resort to syncing with their iTunes. After that, I untrust the friend’s computer from my iPhone.
These are just two common examples of when untrusting computers may be necessary.
Each user has his or her own needs and specific ways of doing things, so you might want to untrust all computers from your iOS devices for reasons not stated above.
Things to know before untrusting devices
The below method of untrusting devices will reset all location and privacy settings on your iPhone, iPad, or iPod touch, so you’ll need to recreate them afterward. Though a tad clunky, this workaround is more user-friendly versus resetting the entire device to its factory settings, like on iOS editions prior to iOS 8.
Another small catch: untrusting a computer from your iOS device will also reset the Trust This Computer alert on that device for all computers it has connected to.
How to untrust your computer from iPhone and iPad
- Open the Settings app and go to General > Transfer or Reset iPhone.
- Tap Reset.
- Pick Reset Location & Privacy option. You will be asked to enter your device’s passcode if you have set it up.
- Confirm that you wish to reset all location and privacy settings on your device.
- Close the Settings app when complete.
Tip: Now is a good time to recreate your location and privacy customizations. Just visit the Privacy section within the Settings app to customize the location and privacy settings to what you had prior to the reset.
Another method of untrusting computers from iOS devices
If you don’t like the idea of resetting your privacy and location settings just to break all trusted connections, you can just as easily untrust all computers by resetting your network settings.
Simply navigate to Settings > General > Transfer or Reset iPhone > Reset and tap Reset Network Settings. This will also reset your network settings and saved Wi-Fi passwords so you’ll need to recreate these items at a later stage.
Tip: Wiping your device clean also untrusts all connected computers.
Can you trust that computer again?
Yes, you can. When you connect your iPhone or iPad to iTunes, Finder, Image Capture, Photos app, etc., with a USB connection, the familiar dialog box with Trust and Don’t Trust options will appear on the screen of your iOS device.
Hit Trust to give iTunes/Finder access to your iOS device. If you tap on Don’t Trust, you’ll see this alert each time you connect your device to that computer. If your iOS device is passcode locked, you need to unlock it before you see the alert.
Click Accept if you’re about to sync the device with iTunes or Finder.
Note: On recent versions of macOS, like macOS Ventura, you first have to click Allow from the Allow accessory to connect alert or Finder. Once you do that, you will see the Trust This Computer alert on your iOS or iPadOS device.
What to do if the Trust alert isn’t showing up?
In some rare cases, the Trust This Computer alert may not even show up when it’s supposed to. So what do you do? Here are some of the things you can try:
- Turn everything off and on again: In the unlikely event that a USB port’s driver has failed to initialize, try restarting the computer. It doesn’t hurt to restart the iOS device at the same time. Afterward, try connecting again.
- Update iTunes: An outdated version of iTunes on Windows PC can and will cause this problem. It’s a part of Apple’s verification process. Make sure you have the latest version of iTunes by checking here.
- Reseat the device: In some cases, the USB connection could have failed or malfunctioned. Try unplugging the device and using a different USB port.
- Try another USB cable: If the iPhone Lightning cable or USB-C cable of your iPad is bad, you won’t ever get an alert. Try another cable and see if the issue persists. Non-MFi Lightning cables are notorious for these issues.
- Reset your device’s trust settings again: Try the steps above to reset location and privacy, which should allow you to finally trust the computer.
- Reset your device’s network settings: If the above didn’t work, you can also try resetting your network settings. This can sometimes get things working in a flash too.
- Worst case scenario – contact Apple: If the trust alert still isn’t coming up, contact Apple for support.