If you're trying to update or restore an iPhone and get an Error 9 message, there may be a connection problem between iTunes and software on your system. If iTunes or your computer aren't running the most current software, updating may get the process working again. If this doesn't work, troubleshoot security software, and the connections between the iPhone and the computer.
Check for Updates
Open iTunes. Select the Help button and then Check for Updates. If an update is available, install it.
If you're running automatic updates on Windows, your system should be up to date. You can still check for updates and should do so if you've disabled automatic downloads.
Type settings from your Home screen to start a search and select PC Settings when it appears in the list. Select Update and Recovery.
If you're using automatic updates, check the system's status by selecting Check Now. If you've disabled automatic updates, you may see other options, such as Check for Updates. Once you've run the check, select View Details to see a list of updates and install them.
Once you've updated, disconnect the iPhone from the computer, if it's still connected, and close iTunes. Close down the computer and restart it. Open iTunes, reconnect the iPhone and see if you can complete the update or restore.
Disable Security Software Programs
Sometimes, anti-virus software and firewalls block your computer's access to Apple's servers, preventing you from updating or restoring the iPhone. Check if this is the problem by disabling security programs temporarily.
Once the software is disabled, open iTunes, connect the iPhone and try the process again. If it works now, the security software was the problem.
Check Your Connections
You may also see an Error 9 message if an update or restore was interrupted. For example, this may happen if your computer lost its Internet connection during the process, or if there is a problem with the USB cable or port you use to connect the iPhone to the computer.
Check that you're online and have a stable connection; if not, troubleshoot your Wi-Fi. If your connection is working OK, check the iPhone's cable and the computer's USB port.
Check the Cable
Examine the cable for signs of wear or damage; check each end to make sure the connectors are free from dust or debris. If the cable is damaged or worn, it may not provide a stable connection and may cut out. If you have a spare Apple USB cable, try using that.
Check the USB Port
Make sure you're using a direct USB port on your computer. If you're plugged into a keyboard port or are using a hub, the port may not provide enough power to run the process, triggering the error message.
If you have another USB port, try switching the cable to that one. If you have other non-essential devices connected to the system by USB, disconnect them in case they are interfering with the restore or update.