unknown error 4000

Error 4000 is a Windows and iTunes error. For some reason, when you try to update in iTunes, when the device restarts, Windows cannot unlock the device because of the password. Until Apple provides a fix to iTunes a workaround is to temporarily disable your passcode on the iPhone, do your update, then restore the passcode on the iPhone. A con to that is that it will remove all of your cards in your Apple Wallet. You also have the option to update over the air by going to Settings>General>Software Update and follow the screen prompts.

The support article that the Community Specialist does not address this error message. That error indicates a bug in iTunes for Windows that Apple still has not addressed. Here are some things that will allow you to update.

• Temporarily disable your phone’s passcode before updating. When you do this, you lose all information in Apple Wallet and will have to enter it again.
• Downgrade iTunes to version 12.8 on your PC if you are able to do so.
• Update over the air by going to Settings/General/Software Update

Updating over WiFi may be the easiest way to do this if you have access to a reliable WiFi network.

Greetings reyesmalexander,

We understand that you are having some difficulty updating your iPhone, and we'd like to help. Begin by following the guidance found here:

If you see an error when you update or restore your iPhone, iPad, or iPod

Take care.