iTunes: Specific update-and-restore error messages and advanced troubleshooting
Did you try these basic troubleshooting steps first? If the issue persists, continue with these advanced troubleshooting steps.
The alert message in iTunes may include one of the following numbers (or the message may include a number not listed here): -1, 2, 4, 6, 9, 13, 14, 20, 21, 23, 26, 28, 29, 34, 35, 36, 37, 40, -48, -50, 1000, 1002, 1004, 1011, 1013, 1014, 1015, 1479, 1600, 1601, 1602, 1603, 1604, 1611, 1631, 1638, 1639, 2001, 2002, 2005, 2006, 2009, 3002, 3004, 3013, 3014, 3015, 3194, 3200, 4000, 4005, 4013, 4014, 4016, 239006, 9807, -9808, 9844, 4026xxxxx.
Click the link for the error code you have. If it's not listed here, check the error messages below and, if necessary, follow the steps below to resolve the issue.
Specific error messages and resolutions
Error 3194 or "This device is not eligible for the requested build"
Learn more about Error 3194.
Error 20, 21, 23, 26, 28, 29, 34, 36, 37, and 40
Also, check your hosts file to verify that it's not blocking iTunes from communicating with the update server. See the steps under the heading "Blocked by configuration (Mac OS X / Windows) > Rebuild network information > Mac OS X > The hosts file may also be blocking the iTunes Store." If you have software used to perform unauthorized modifications to the iOS device, uninstall this software prior to editing the hosts file to prevent that software from automatically modifying the hosts file again on restart.
If the issue isn't resolved by USB isolation troubleshooting and another computer isn't available, try these steps to resolve the issue:
- Connect the device to iTunes.
- Confirm that the device is in Recovery Mode. If it's not in Recovery Mode, put it into Recovery Mode.
- Restore and wait for the error.
- When prompted, click OK.
- Close and reopen iTunes while the device remains connected.
- The device should now be recognized in Recovery Mode.
- Try to restore again.
If the steps above don't resolve the issue, try restoring using a known-good USB cable, computer, and network connection.
Error 1600, 1601, and 1602
Error 4000, 4005, 4013, 4014, and 4016
- Restart your computer.
- Disconnect all your USB devices from your computer and connect to another USB port.
- Use a different USB cable.
- Uninstall third-party security software.
- Try restoring using an alternate computer.
Error 13, 14, 35 and 50 (or -50)
- Perform USB isolation troubleshooting, including trying a different USB port directly on the computer. See the advanced steps below for USB troubleshooting.
- Put a USB 2.0 hub between the device and the computer.
- Try a different Dock Connector or Lightning Connector to USB cable.
- Eliminate third-party security software conflicts.
- There may be third-party software installed that modifies your default packet size in Windows by inserting one or more TcpWindowSize entries into your registry. An incorrectly set default packet size can cause this error. Contact the software manufacturer that installed the packet-size modification for assistance. Or, follow this article by Microsoft to reset the packet size back to the default for Windows: How to reset Internet Protocol (TCP/IP).
- Connect your computer directly to your Internet source, bypassing any routers, hubs, or switches. You may need to restart your computer and modem to get online.
- Try to restore from another known-good computer and network.
Error 2000-2009 (2001, 2002, 2005, 2006, 2009, and so on)
Restore loop (being prompted to restore again after a restore successfully completes)
There was a problem downloading the software for the iPhone (or another iOS device)
iTunes can't connect to the iPhone because an invalid response was received from the device
Unknown Error containing "0xE" when restoring
Hang during restore process
Troubleshooting security software will frequently resolve this issue. An incorrectly set default packet size can cause this issue. There may be third-party software installed that modifies the default packet size in Windows by inserting a TcpWindowSize or MaxGlobalTcpWindowSize entry into the Registry. Contact the manufacturer of the software that installed the packet-size modification for assistance in adjusting the TcpWindowSize values.
Typically the default packet size is modified by:
- 3G cellular network card software
- ISP communication software
- Internet speed download optimization software
There are legitimate reasons to change the TCP/IP packet size and not use the Windows default settings (for example, network traffic optimization, home/broadband optimization, enterprise app optimization such as database apps, Exchange, and more). Deleting the TcpWindowSize or GlobalMaxTcpWindowSize entries in Windows Registry could affect the system's performance with other apps or on their network connections. Deleting the customized TCP/IP settings may require the reinstallation of any third-party applications that had modified the TCP/IP settings from the Windows default settings.
There are two ways to resolve this:
- Follow this article by Microsoft: How to reset Internet Protocol (TCP/IP).
- Follow the steps below to manually find and remove TcpWindowSize and MaxGlobalTcpWindowSize entries from the Registry.
- Navigate to the C:\Windows folder and launch Regedit.
- Choose Edit > Find.
- Search for TcpWindowSize entries. There are typically multiple entries of TcpWindowSize/GlobalMaxTcpWindowSize spread throughout the entire Registry. If TcpWindowSize exists, one or more third-party applications have changed the user's default Windows settings for TCP/IP.
- Choose File > Export. This step will export a copy of the Registry that can be used as a backup of the original settings.
- Delete the TcpWindowSize entry.
- Search for the next TcpWindowSize entry and delete each one until the Registry no longer has any TcpWindowSize entries.
- Close Regedit, restart the PC, and test.
If you're uncertain as to why these registry entries exist and the PC is a business computer, contact your network administrator and determine what TCP/IP values can be set in their Windows Registry setting so that the PC can update or restore an iOS device rather than deleting the TcpWindowSize entry.
If editing the registry doesn't resolve the issue, restoring on a different computer that didn't install the communication software is the step most likely to resolve this issue.
Additional error codes and resolutions
Unable to contact the iOS software update server gs.apple.com
- Install the latest version of iTunes.
- Check security software and ensure that communication to gs.apple.com is allowed. Follow these steps for assistance with security software.
- Check the hosts file. The restore will fail if there is an active entry to redirect gs.apple.com. Follow the advanced iTunes Store troubleshooting steps to edit the hosts file or revert to a default hosts file. See "Blocked by configuration: (Mac OS X/Windows) > Rebuild network information."
- Try to restore from another known-good computer and network.
- If the errors persist on another computer, the device may need service.
Network connection or download errors
Error 1479: This error occurs when trying to contact Apple for an update or restore.
- Quit iTunes
- Disconnect from USB and restart the iOS device.
- Reconnect the device to the computer.
- Launch iTunes and attempt to update or restore again.
Error 1639: Follow these steps.Errors 3000-3999 (3004, 3013, 3018, 3164, 3194, and so on): Error codes in the 3000 range generally mean that iTunes can't contact the update server (gs.apple.com) on ports 80 or 443.
- Update to the latest version of iTunes.
- Verify the computer's date and time are accurate.
- Check that your security or firewall software isn't interfering with ports 80 or 443 or with the server gs.apple.com.
- Follow these steps to troubleshoot security software. Often, uninstalling third-party security software will resolve these errors.
- An entry in your hosts file may be redirecting requests to gs.apple.com (go to "Unable to contact the iOS software update server gs.apple.com" above).
- Internet proxy settings can cause this issue. If you're using a proxy, try again without using a proxy.
- Test restoring while connected to a known-good network.
Error 3002: If you experience this error while updating an iPod touch (2nd generation) or iPhone 3G, please use the standard update or restore process in iTunes (click Update or Restore).
Error 3194: You may not have the latest version of iTunes installed. Update to the latest version of iTunes. If the issue persists, follow the steps above in "Unable to contact the iOS software update server gs.apple.com."
Error 3004: If you're using a Mac, you may be able to resolve an error 3004 by quitting iTunes and using the following command in the command line: dscacheutil -flushcache.
The device couldn't be restored. An internal error occurred or Error 3200: This indicates a network-connectivity or traffic issue. If you see this error, wait an hour or more and try again.
Error 9807: Verify the computer's date and time.
If unresolved, open access to the following VeriSign servers:
Access to these servers may be blocked by security software, content filtering software, a misconfigured router, or anti-spyware software. For iTunes for Windows, follow these steps to troubleshoot security software issues.
Error 9808 (or -9808): Follow the steps for an unknown alert message when connecting to resolve the issue. If those steps don't resolve the issue, or if the settings revert to their original values after the restart, then follow the steps to troubleshoot security software issues.
Error 9844: This is typically caused by incorrect firewall settings. Go to "Open the proper ports and allow access to Apple servers" in the "Advanced steps" section below.
Errors related to third-party security software
Error 2, 4 (or -4), 6, 1000, and 9006
- Follow the steps to troubleshoot security software. Often, uninstalling third-party security software will resolve these errors.
- There may be third-party software that modifies your default packet size in Windows by inserting a TcpWindowSize entry into your registry. An incorrectly set default packet size can cause these errors. Contact the manufacturer of the software that installed the packet size modification for assistance or follow this article by Microsoft: How to reset Internet Protocol (TCP/IP).
- Verify that access to ports 80 and 443 are allowed on your network.
- Verify that communication to albert.apple.com or phobos.apple.com isn't blocked by a firewall or other Internet security setting.
- Discard the .ipsw file, open iTunes and attempt to download the update again. See the steps under "Advanced steps > Rename, move, or delete the iOS software file (.ipsw)" below for file locations.
- Restore your device while connected to a different network.
- Restore using a different computer.
Errors related to downgrading iOS
The required resource can't be found: This alert message occurs when your device has a newer version of iOS than what is available in iTunes. When troubleshooting a device that presents this alert message, go to Settings > General > About and check the version of iOS on the device. If it's newer than the latest released iOS version, the device may have a prerelease developer version of iOS installed. Installing an older version of iOS over a newer version isn't supported.
Error 1015: This error is typically caused by attempts to downgrade the software for an iPhone, iPad, or iPod touch. This can occur when you attempt to restore using an older .ipsw file. Downgrading to a previous version isn't supported. To resolve this issue, attempt to restore with the latest iPhone, iPad, or iPod touch software available from Apple. This error can also occur when an unauthorized modification of the iOS has occurred and you're now trying to restore to an authorized, default state.
Possible hardware issues
Error 1002, 1011, 1012, and 1014: These errors may indicate a hardware issue with your device. Follow the steps in this article and attempt to restore while connected with a known-good 30-pin Dock Connector cable, computer, and network to isolate this issue to the device. A missing MAC address or a default IMEI value (00 499901 064000 0) can also confirm a hardware issue.
Error 48 (or -48): Quit iTunes, discard the .ipsw file (see the steps under "Advanced steps > Rename, move, or delete the iOS software file (.ipsw)" below for file locations), open iTunes, and attempt to download the update again.
Error 20000-20008: This error may indicate that you have a USB communication failure due to a damaged USB 30-pin Dock Connector cable, out-of-date USB device drivers or firmware, or that other USB devices connected to your computer are interfering with iTunes communicating to the iOS device. Try restarting the PC and testing again with a different USB port. If you're using a custom Windows Theme Pack, revert to the default theme pack, restart, and try to restore.
Error 40265xxxx: Errors of the 40265xxxx range generally occur during the restore-from-a-backup phase, after iOS has been installed on the device. Restoring the device and setting up as new can resolve the issue. Follow the steps to back up your data and set up as a new device.
Follow these advanced steps only if these steps haven't resolved the issue or if a specific update and restore error message recommends it. If the update or restore error message isn't listed above, try following all these steps and the steps in this article starting from the top down (basic to advanced steps) to resolve the issue.
Force restart your iOS device
Hold down the Home and Sleep/Wake button until the Apple appears and then release. Once the device has started up or displays a "connect to iTunes" screen, try to restore again.
Restore on a different computer
If the issue isn't resolved by the above steps:
- Try to restore using a different computer.
- Ensure that the computer you use has an active connection to the Internet, the latest version of iTunes, other USB devices except the keyboard and mouse have been disconnected.
- Connect directly to a rear USB 2.0 port on the computer.
If another computer isn't available, continue with the steps below.
Open the proper ports and allow access to Apple servers
During the update and restore process, iTunes needs to contact Apple. Ensure that your computer has the following ports open and can access these servers:
- Port 80
- Port 443
Note: iTunes makes a secure connection over the Internet to the above servers. Since it's a secure connection, it's especially critical that your computer's date and time are correct.
To learn how to open your network to access these servers, refer to your router, firewall, or security software documentation. Follow the steps to identify, update, and configure third-party security software to resolve a restore error.
You may need to update, properly configure, disable, or uninstall built-in firewalls and other security software to prevent interference with iTunes. For assistance with this, contact the company that supports the firewall or security software you use. If you're using proxy settings, try to restore or update without using a proxy.
Use MSConfig to restart your PC using Selective Startup
On a PC, try to restore your iPhone, iPad, or iPod touch after restarting in Selective Startup mode. Don't use MSConfig to resolve restore issues caused by security software. For instructions on how to use MSConfig to restart your PC in Selective Startup with the appropriate Apple software enabled, see the following steps:
Stop Virtual OS environments
OS virtualization or emulation software may cause restore errors. If you're using a Mac and have a virtual OS environment running or attempting to restore from iTunes running in a virtual OS, shut down the virtual OS, quit the virtualization software, and attempt to restore using the latest version of iTunes available for the Mac.
Restore using a new user account
Create a new user account on your computer and try to restore while logged in as the new user. iTunes will download a new version of the software restore file. After creating the new user, log in to that account, open iTunes, and attempt to restore to see whether the issue persists in this new user.
Use these steps if you're not sure how to create a new user:
- Windows XP: Follow the steps in this Microsoft article.
- Windows Vista: Follow the steps in this Microsoft article.
- Windows 7: Follow the steps in this Microsoft article.
- Windows 8: Follow the steps in this Microsoft article.
Mac OS X
- Choose Apple () > System Preferences.
- Choose View > Accounts.
- Click the "+" (you may need to authenticate to be able to click this).
- Give the new user a name, short name, and password.
- Select "Allow user to administer this computer." This makes the user an administrator user.
- Click Create Account.
Rename, move, or delete the iOS software file (.ipsw)
iTunes uses IPSW files to restore your device. If those files are unusable, try deleting them, renaming them, or moving the file to a different directory. This will cause iTunes to download a new copy of the IPSW. When a restore issue is specific to a user, it's likely due to an unusable .ipsw file. If removing the .ipsw file doesn't resolve a user-specific restore issue, then the issue is caused by other user-specific security software settings or iTunes preferences. Creating a new user will also cause new .ipsw restore files to be downloaded in the new user. You can find the .ipsw files in these locations.
Mac OS X
|iPhone||~/Library/iTunes/iPhone Software Updates|
|iPad||~/Library/iTunes/iPad Software Updates|
|iPod touch||~/Library/iTunes/iPod Software Updates|
|Note: The tilde "~" represents your Home directory.|
|iPhone||C:\Documents and Settings\[username]\Application Data\Apple Computer\iTunes\iPhone Software Updates|
|iPad||C:\Documents and Settings\[username]\Application Data\Apple Computer\iTunes\iPad Software Updates|
|iPod touch||C:\Documents and Settings\[username]\Application Data\Apple Computer\iTunes\iPod Software Updates|
|Note: To quickly access the Application Data folder, choose Start > Run. Type %appdata% and click OK.|
Windows Vista, 7, and 8
|iPhone||C:\Users\[username]\AppData\Roaming\Apple Computer\iTunes\iPhone Software Updates|
|iPad||C:\Users\[username]\AppData\Roaming\Apple Computer\iTunes\iPad Software Updates|
|iPod touch||C:\Users\[username]\AppData\Roaming\Apple Computer\iTunes\iPod Software Updates|
|Note: To quickly access the AppData folder, click Start, type %appdata% in the search bar, and press the Return key.
Windows 8: Move the cursor to the upper right, click the magnifying glass, type %appdata%, and press the Return key.
Restart the Apple Mobile Device Service (Windows only)
Restarting the Apple Mobile Device service on Windows may allow you to successfully restore your device.
Remove and reinstall iTunes and Apple Mobile Device Support
Completely remove iTunes and Apple Mobile Device support and then reinstall the latest version of iTunes. Click the appropriate link below for instructions on how to accomplish this for your operating system.
- Windows XP
- Windows Vista, Windows 7, and Windows 8
- Mac OS X v10.6.8 and earlier
- For OS X Lion v10.7, removing iTunes isn't necessary. Download iTunes and reinstall it.
After removing and reinstalling the latest version of iTunes, try restoring the iOS device again.
If you have performed all of the steps in this article and you're still experiencing a restore issue, contact Apple or your wireless carrier, whichever provides phone support for your device. If you use an iPhone, contact your iPhone wireless carrier. Wherever you live in the world, you can find your service options at Apple Support & Service Options.