during update or restore your iPhone, iPad, or iPod touch with iTunes, the update or restore process may stop, and you may see an alert message in iTunes.

Hang during restore process: Following iTunes for Windows: Troubleshooting security software will frequently resolve this error. This error can be caused by the default packet size being set incorrectly. There may be third-party software installed that modifies your default packet size in Windows by inserting a TcpWindowSize entry into your Registry. Contact the manufacturer of the software that installed the packet-size modification for assistance.

Cannot be restored. This device is not eligible for the requested build: If you receive this error, you likely do not have the latest version of iTunes installed. Check http://www.apple.com/itunes/download/ for the latest available version of iTunes. If you do have the latest version of iTunes, this can occur when you attempt to restore using an older .ipsw file. Downgrading to a previous version is not supported.

Restore loop (being prompted to restore again after a restore successfully completes): This issue is typically caused by out-of-date or incorrectly configured third-party security software. Please follow iTunes for Windows: Troubleshooting security software issues if USB troubleshooting does not resolve this issue.




Error 2: This error is frequently resolved by disabling or uninstalling third-party security or firewall software.

Error -4: This error may occur because of one of the following conditions:

* Access to ports 80 and/or 443 are blocked.
* Communication to albert.apple.com and/or phobos.apple.com is blocked by a firewall, third-party security software, or other Internet security settings.
* The iTunes Store is experiencing extremely high traffic.

Error 6: All of the steps in this article apply to resolve this issue. Following iTunes for Windows: Troubleshooting security software frequently resolves this error. There may be third-party software installed that modifies your default packet size in Windows by inserting a TcpWindowSize entry into your Registry. If your default packet size is set incorrectly it can cause this error. Contact the manufacturer of the software that installed the packet size modification for assistance.

Error 9: This error occurs when the device unexpectedly drops off of the USB bus and communication stops. This can occur if the device is manually disconnected during the restore process. This issue can be resolved by performing USB isolation troubleshooting, using a different USB dock connector cable, trying another USB port, restoring on another computer, or by eliminating conflicts from third-party security software.

Error 13 and 14: These errors are typically resolved by performing one of more of the steps listed below:

1. Perform USB isolation troubleshooting, including a different USB port directly on the computer.
2. Put a USB 2.0 hub between the device and the computer.
3. Try a different USB 30-pin dock connector cable.
4. Eliminate third-party security software conflicts.
5. 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. If your default packet size is set incorrectly it can cause this error. Contact the manufacturer of the software that installed the packet size modification for assistance.
6. 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.
7. Try to restore from another known-good computer and network.

If you find an ASR error 1000 in the iPhone, iPad, or iPod updater log file, that is an error decompressing and transferring the IPSW file that is downloaded during the restore. This error is frequently caused by third-party security software interference, a poor quality Internet connection resulting in a bad IPSW download, or a conflict on the USB bus.

Error 18 (or -18): This occurs when the media library on the device is corrupt and cannot be modified or updated. Updating to the latest version of iTunes and then restoring should resolve this issue.

Error -19: The full text of this error is: "iTunes could not sync to the iPhone '[iPhone name]' because an unknown error occurred (-19)". This error can occur when you attempt to update an iPhone 3G to a later version of the software and iTunes attempts to back up iPhone while it is syncing. To resolve this issue:

1. Uncheck "Automatically sync when this iPhone is connected" from the iTunes Summary tab.
2. Eject iPhone.
3. Reconnect iPhone.
4. Select Update.

Error 20, 21, 34, 37: These errors typically occur when security software interferes with the restore and update process. If you are using a PC, follow this article to resolve this issue.

Error 23, 28, 29, 1002, 1011, 1012, 1013, 1014, 1611: These errors may indicate a hardware issue with your device. Follow the steps in this article and also attempt to restore while connected with a known-good 30-pin Dock Connector cable, computer, and network to isolate this issue to the device. If the MAC address is missing or the IMEI is the default value (00 499901 064000 0), this can also confirm a hardware issue.

Error 48: To resolve this error, follow the steps in this article. Also see the steps in "Restore using a new user account" above for .ipsw file locations.

Error 1015: This error is caused by attempts to downgrade the iPhone, iPad, or iPod touch's software. This can occur when you attempt to restore using an older .ipsw file. Downgrading to a previous version is not supported. To resolve this issue, attempt to restore with the latest iPhone, iPad, or iPod touch software available from Apple.

Error 1479: This error occurs when trying to contact Apple for an update or restore. Quit iTunes, disconnect from USB, restart the iOS device, reconnect the device to the computer, then launch iTunes and attempt to update or restore again.

Error 1602: Try the following steps to resolve this error:

1. Ensure proper USB isolation troubleshooting has been performed, and test with a known-good cable.
2. Follow the steps listed for Error 1604.
3. This error may be resolved by disabling, deactivating, or uninstalling third-party security, antivirus, and firewall software. See steps in this article for details on troubleshooting security software.

Error 1603: If you receive this error and the iOS device is not automatically placed into recovery mode, it may be necessary to do so manually. Refer to iPhone and iPod touch: Unable to restore for steps on placing iPhone into forced recovery mode. Also, remove the IPSW and attempt to restore again. If you do not want to remove the IPSW in the original user, try restoring in a new administrator user.

Error 1604: This error is often related to USB timing. Try changing USB ports, uninstalling and reinstalling USB ports, and other available USB troubleshooting steps (troubleshooting USB connections, device not recognized properly, computer won't recognize a FireWire or USB device). If you are using a dock, bypass it and connect directly to the USB 30-pin dock-connector cable. If the issue persists on a known-good computer, the device may need service.

If the issue is not resolved by USB isolation troubleshooting, and another computer is not available, try these steps to resolve the issue:

1. 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.
2. Restore and wait for error 1604.
3. When prompted, click OK.
4. Close and re-open iTunes while iPhone remains connected.
5. iPhone should now be recognized in Recovery Mode again.
6. Try to restore again.

If the steps above do not resolve the issue, try restoring using a known-good USB cable, computer, and network connection.

Error 2000-2009: (2001, 2002, 2005, 2006, 2009, and so on) If you experience this issue on a Mac, disconnect third-party devices, hubs, spare cables, displays, reset the SMC, and then try to restore. Learn how to reset the SMC. If you are using a Windows computer, remove all USB devices and spare cables other than your keyboard, mouse, and the device, restart the computer, and try to restore. If that does not resolve, try the USB issue-resolution steps and articles listed for Error 1604 above. If the issue continues, it may be related to conflicting security software.

Error 3000-3999: (3002, 3004, 3013, 3014, 3164, 3194, and so on) Error codes in the 3000 range generally mean that iTunes cannot contact the gs.apple.com server on ports 80 or 443. This may be because out-of-date or incorrectly configured security or firewall software is interfering, or due to your Internet proxy settings. If you are using a proxy, try without using one or with a known-good network. If that does not resolve the issue, follow iTunes for Windows: Troubleshooting security software issues. Error 3014 may indicate that you need to free up more disk space on the computer before trying to restore again.

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 3004: If the steps listed in Error 3000-3999 do not resolve, you may be able to resolve an error 3004 by quitting iTunes and using the following command at the command line: dscacheutil -flushcache

Error 9807: If you see "Error 9807", open access to the following VeriSign servers:

* evintl-ocsp.verisign.com
* evsecure-ocsp.verisign.com

Error 9808: Follow the steps in iTunes Store: Unknown alert error message when connecting to resolve the issue. If those steps do not resolve the issue, or if the settings revert to their original values after the restart, then follow iTunes for Windows: Troubleshooting security software issues.

Error 9844: Error 9844 is typically caused by incorrect firewall settings. See the top of this article for ports and servers that must be open.

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. Before restoring as new, take steps to preserve the previous backups created by iTunes, such as copying the contents of the Backup directory onto the desktop. See iPhone and iPod touch: About backups to learn where backups are stored for your computer's operating system and additional precautionary notes regarding setting up as new. The backups created by iTunes store data such as your SMS, Favorites, Bookmarks, and other app data.

If you have performed all of the steps in this article and you are still experiencing a restore issue, contact Apple or your wireless carrier, whichever provides phone support for your device. To find Apple's contact information in your country, refer to Contacting Apple for Support and Service. If you use an iPhone 3G or iPhone 3GS, you can find your wireless carrier at Locating iPhone wireless carriers. Wherever you live in the world, you can find your iPhone service options at the Online Service Assistant.