When updating iPhone 12, what does error code 4000 mean?

You have 2 solutions to fix the issue:

1. Remove the password on your device, update and re-create your password (which may be the same, of course), or
2. Update via Wi-Fi, without using a cable. On your device go to Settings > General > Software Update.

Im just saying it will certainly help and Apple suggests doing this in the troubleshooting document: iOS update and restore errors. Otherwise restart everything, the phone, computer. I don’t use a computer to update my phone. I do it over the air from iPhone settings but of course it’s always wise to have an iCloud back up. That way if anything gets lost you can retrieve it or restore from back up: How to back up your iPhone, iPad, and iPod touch with iCloud - Apple Support. Keep the iCloud back up turned on all the time or choose back up now. Settings- Apple ID- iCloud Backup. Then update your phone from Settings- General - Update

On Windows: Update to latest version of iTunes.

Vancouver22 wrote:

On Windows: Update to latest version of iTunes.

Hello Vancouver22,

I've been waiting for a new release of iTunes to fix the issue. Are you confirming that the latest version of iTunes fixes this issue?

https://discussions.apple.com/thread/252712830

apple explains what it is here.

yse is expended

Oops, never mind, I had the wrong thing. I apoligize.