Are you unable to update or restore your iPhone? This troubleshooting assistant can help.
Make sure your computer has the following:
USB 2.0 port
The latest version of iTunes
Access to a Wi-Fi network
and one of the following operating systems:
Mac OS X version 10.5.8 or later
Windows 7; Windows Vista; or Windows XP Home or Professional with Service Pack 3 or later
Check USB connections
When updating or restoring, connect iPhone to a USB port that is built into the computer instead of the keyboard or an external USB hub.
Remove all USB devices other than your mouse, keyboard, and iPhone.
Use the Dock Connector to USB cable that came with iPhone
If your computer has USB ports on the front and back, use a USB port in the back
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