Get help with iOS update and restore errors

When you update or restore your iPhone, iPad, or iPod touch in iTunes, you might see this message: "The iPhone [device name] could not be restored. An unknown error occurred [error number]."

Here's how to solve specific iOS update and restore errors.

Try these steps first

Use the basic troubleshooting steps to solve most update and restore issues.

Try these steps next

If you tried the basic steps and still see the error message, find your error number and follow the advanced steps below.

12346910111213141617202123262728293435363740,

1002100410111012101310141015

1600160116021603160416111638, 1643-165016671669

200120022005200620093002300430133014301531943200

4005401340149006

Solve network errors

Related errors: 17, 1638, 3014, 3194, 3000, 3002, 3004, 3013, 3014, 3015, 3194, 3200, or "There was a problem downloading the software," or "The device isn't eligible for the requested build." These alerts mean that your computer is either having difficulty contacting the Apple update server or communicating with your device. 

Check your computer for software or settings that might cause communication issues between your computer and Apple or between your computer and your device.

Check your security software

Related errors: 2, 4, 6, 9, 1611, 9006. Sometimes security software can stop your device from communicating with either the Apple update server or with your device.

Check your security software and settings to make sure that they aren't blocking a connection to the Apple servers.

Check your USB connections

Related errors: 13, 14, 1600, 1601, 1602, 1603, 1604, 1611, 1643-1650, 2000, 2001, 2002, 2005, 2006, 2009, 4005, 4013, 4014, or "invalid response."

If the USB connection between your device and computer is interrupted, you might not be able to update or restore.

To narrow down the issue, you can try different equipment:

If you still see the error message, check for hardware issues by following the next section.

Check for hardware issues

Related errors: 1, 3, 11, 12, 13, 14, 16, 20, 21, 23, 26, 27, 28, 29, 34, 35, 36, 37, 40, 1002, 1004, 1011, 1012, 1014, 1667, or 1669.

These errors mean that your device or computer might have a hardware issue that stops the update or restore from completing.

  1. Check that your security software and settings aren't blocking your device from communicating with the Apple update server.
  2. Then try to restore your iOS device two more times while connected with a cable, computer, and network you know are good.
  3. Make sure that your security software and settings are allowing communication between your device and update servers.
  4. If you still see the error message when you update or restore, contact Apple support.

Check for outdated or modified software

Related errors: 1015, "The required resource can't be found."

You might see these errors if any of these are true:

  • Your version of iTunes is out of date. Get the latest version of iTunes and try to update or restore again.
  • Your device has a beta version of iOS.
  • You're trying to install an earlier version of iOS (downgrading).
  • Your device has unauthorized modifications to iOS, also called "jailbreaking."

Use recovery mode to restore your device to the latest version of iOS.

User-specific issues and .ipsw (errors 48 and 1015)

If a new .ipsw file doesn't solve a user-specific restore issue, other user-specific security software settings or iTunes preferences is causing the issue.

Error 1015 might happen in a new user if the customer performed unauthorized modifications to the iOS device. In these cases, the installed firmware is a higher version than the supported firmware.

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