- Error 17
- Error 1639
- Errors 3000-3020
- Error 3194
- Errors 3100-3999
- This device isn't eligible for the requested build
If you see one of these messages and need help updating or restoring your iOS device, install the latest version of iTunes and try to update or restore again. If you need more help, follow these steps.
Check your hosts file
After you update iTunes to the latest version, check the hosts file to make sure your computer can contact the update server.
If you’re using a Windows computer, follow the steps in this Microsoft support article (note that resetting the hosts file will affect software services that rely on hosts file redirects). If you're using Windows on a business computer, consult your IT department to be sure applications will work correctly after you reset the hosts file.
If you're using a Mac, follow these steps:
- In the Finder, choose Applications > Utilities.
- Open Terminal.
- Enter this command and press Return:
sudo nano /private/etc/hosts
- Enter the password you use to sign in to your computer and press Return. You won't see text appear in the Terminal window when you enter the password. Make sure you use a nonblank administrator password.
- Terminal will display the hosts file.
- Navigate using the arrow keys and look for an entry containing “gs.apple.com”.
- Add the # symbol and a space ("# ") to the beginning of the gs.apple.com entry.
- Press Control-O to save the file.
- Press Enter when asked for the filename and Control-X to exit the editor.
- Restart your computer.
- Try to update or restore your iOS device again.
Address TCP/IP filtering, firewall, or security software
If you have TCP/IP filtering, firewall, or security software installed on your computer, follow these steps.
- Follow these steps to configure or temporarily uninstall your security software.
- Bypass your Internet router. Some routers might block iTunes from accessing the update server. If you're using a router that isn't manufactured by Apple, try these steps.
- Disconnect from your wired or wireless router.
- Use an Ethernet cable to connect directly to your modem.
- Restart your computer and modem. Contact your Internet service provider for instructions on using your modem.
- Be sure you have a working Internet connection by visiting www.apple.com. See these steps for help or contact your Internet service provider.
- If your Internet connection is working, try to update or restore your iOS device again.
Restore or update on another computer
Try to restore or update on another computer with a different Internet connection. This will help rule out other issues on your computer that might stop iTunes from communicating with the update server.
Errors 1639, 3000-3020, and 3100-3999 (with the exception of 3194) are sometimes caused by your network settings. If your computer uses a managed network, refer to your network administrator. Proxies, firewalls, and other network security measures can cause these errors. If necessary, find a different network connection to restore the device. For example, if you're restoring at work, try to restore at home or on a friend's computer and network.