How to fix itunes error 16xx on restore ios process

On Mac:
* Open Finder
* Hold down COMMAND + SHIFT keys and press 'G'
* Enter "/private/etc/" in the field and press "Go"
* Find "hosts" file in the directory
* Drag the file to your desktop
* Open it in text editor
* Remove the line that has gs.apple.com entirely or put a # at the beginning of it to comment it out
* Save the file
* Drag it back to the /private/etc/ folder.
* You'd need to enter your username and password to authenticate the move

On Windows:

* Locate the hosts file in one of the following directories:
Windows 95/98/Me c:\windows\hosts
Windows NT/2000/XP Pro c:\winnt\system32\drivers\etc\hosts
Windows XP, Vista, 7 c:\windows\system32\drivers\etc\hosts
* Right click and click on "Open With..." and then click on "Notepad" on the list.
* Remove the line that has gs.apple.com completely and save the file.

This should work fine