Error 21:
If you see error 53, use these steps.
If you see one of the errors below, you might have a hardware issue:
- 1, 3, 10, 11, 12, 13, 14, 16
- 20, 21, 23, 26, 27, 28, 29, 34, 35, 36, 37, 40, 56
- 1002, 1004, 1011, 1012, 1014, 1667 1669
Here's what to check. Try again after each step:
- If iTunes is already open, quit and reopen it.
- Check your third-party security software.
- Make sure that your USB cable, computer, and network are reliable. Then try twice more to restore your iOS device.
- Check for outdated or modified software.
If you still see the error, contact Apple Support.
Error 9:
When you try to update or restore your iPhone, iPad, or iPod touch, you might see one of these messages in iTunes.
If your iOS device disconnects during the update or restore or if iTunes couldn't tell the device to restore, you might see one of these messages:
- The iPhone [device name] could not be restored. An unknown error occurred (9).
- The iPhone [device name] could not be restored. An unknown error occurred (4005).
- The iPhone [device name] could not be restored. An unknown error occurred (4013).
- The iPhone [device name] could not be restored. An unknown error occurred (4014).
Try these steps:
- Install the latest version of iTunes.
- Force your device to restart:
- On an iPhone X, iPhone 8, or iPhone 8 Plus: Press and quickly release the Volume Up button. Press and quickly release the Volume Down button. Then, press and hold the Side button until you see the Apple logo.
- On an iPhone 7 or iPhone 7 Plus, press and hold both the Side and Volume Down buttons for at least 10 seconds, until you see the Apple logo.
- On iPhone 6s and earlier, iPad, or iPod touch, press and hold both the Home and Top (or Side) buttons for at least 10 seconds, until you see the Apple logo.
- Connect your device to your computer using a USB cable.
- When iTunes asks you to update or restore, click Update (not Restore) to reinstall iOS and keep your personal data.
If you can update, but your device starts up in recovery mode, follow the steps above again. On step 4, choose Restore instead of Update. After the restore completes, you need to set up your device from a backup.
If you continue to see an error during the update:
- Check for updates to your Mac or PC. If you restart your computer for an update, check for updates again after you restart.
- Try to restore your device using another USB cable.
- Try to restore your device on another computer.
If you continue to see error 9, 4005, 4013, or 4014 when you try to restore your iPhone, iPad, or iPod touch, contact us.
