Resolve iOS update and restore errors

When you're updating or restoring 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 resolve specific iOS update and restore errors.

Resolution

Try these steps first

Use the basic troubleshooting steps to resolve 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.

1, 2, 3, 4, 6, 9, 10, 11, 12, 13, 14, 16, 17, 20, 21, 23, 26, 27, 28, 29, 34, 35, 36, 37, 40,

1000, 1002, 1004, 1011, 1012, 1013, 1014, 1015

1600, 1601, 1602, 1603, 1604, 1611, 1638, 1643-1650, 1667, 1669

2001, 2002, 2005, 2006, 2009, 3002, 3004, 3013, 3014, 3015, 3194, 3200

4005, 4013, 4014, 9006

Resolve network errors

Related errors: 17, 1004, 1013, 1638, 3014, 3194, 3000, 3002, 3004, 3013, 3014, 3015, 3194, 3200, or "There was a problem downloading the software," or say 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, 1000, 1611, 9006. Sometimes security software can prevent 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 preventing 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 may be unable to update or restore.
To narrow down the issue, you can also change up your hardware:

• Use the USB cable that came with your device, or a different Apple USB cable. 
• Plug your cable into a different USB port directly on your computer. Don't plug it into your keyboard.
• Try a different computer.
• If necessary, resolve any further issues with the USB connection, then with your security software.

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

Check for hardware issues

Related errors: 1, 3, 10, 11, 12, 13, 14, 16, 20, 21, 23, 26, 27, 28, 29, 34, 35, 36, 37, 40, 1000, 1002, 1004, 1011, 1012, 1014, 1667, or 1669.
These errors mean that your device or computer may have a hardware issue that's preventing the update or restore from completing.

1. Check that your security software and settings aren't preventing 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. Confirm 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 error messages if any of these are true:

• 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.