iOS14 Error 4000

Error 4000 is an undocumented error code (at least publicly undocumented). It means that the connection between the phone and iTunes was interrupted in the middle of a sync or update activity. In the past this might have been caused by a flakey USB port, an antivirus or a firewall. However, there is a new cause of this error that is the result of a bug in iTunes for Windows that requires the phone not be locked during the update. So first check your antivirus and firewall (temporarily disable them), but if that doesn’t fix it there are three workarounds for the bug:

• Update over the air, by going to Settings/General/Software Update
• Downgrade iTunes to version 12.8 if you can find a copy - try https://apple.com/itunes
• Temporarily disable the screen lock passcode on the phone before updating using iTunes on Windows

Note that this error should only be a problem for updates; if you are restoring iOS rather than updating it should not occur.

Turning off your passcode momentarily will solve this problem. But my beef is that Apple should've been out front about this and just notify people that this needs to be done prior to installation of the new iOS. I shouldn't have had to google "iOS error 4000" to find out what the heck was happening. This step wasn't necessary for previous updates. Why the change now?

So guess what worked? The following combined steps:

1. Remove passcode
2. Sign out of iCloud
3. Plug phone into computer, open iTunes and back up phone.
4. Run iOS update from iTunes

Success! :)

I had the same issue when updating iPhone XS from 13.6.1 to 14.2.

You are fully right - disabling Passcode allowed the update process to move forward and finalize the update with no further headaches.

Aram

Thanks a lot. Was able to update software 14.3 after turning off passcode. As I tunes was not able to locate phone as it was never backed up, system asked me to also turn off find my... and it worked. A million thanks to all those who replied.

If you are still having this problem. Here is what worked for me.

1. Backup your connected IPhone on iTunes to your computer.

2 click Restore on top box and restore as new. This will restore the phone to factory settings.

3. Follow the prompts and leave iPhone connected throughout the process

4. When you Get to the screen when it asks which backup to use choose the one that you want and click it.

5. After restore from backup is completed. I saw that newest version on the IPhone was there. Walla!

just disable the passcode and it helped me ...............solved

Another vote for turning off the passcode. Going from IOS 14.1 to 14.4 on iPhone 12 mini. Worked first time after turning off the passcode. Turned back on after the update to 14.4.

Thank you.. Disabling the passcode fixed this

Agreed ! I have also been getting the same issue for both my iPhone X and iPad Pro through PC iTunes update operation. As I do not wish to reinstall Apple Pay cards after disabling the passcode, I updated to iOS 14 and iOS 14.1 through the Settings/General/Software Update menu on each devices. Note that each devices were first backed up on my PC before updating to the new iOS version. I also hope that Apple will fix this lasting bug.

Thank you ,it’s worked for me as well, remove Passcode

it works for me, just disable passcode and do the update

Removing the passcode worked for me too.

Fair enough dude, preferably I’d like Apple to fix this error 4000 is and the OTA bugs when installing iOS 14 installation and OTA and bugs.

Nice article by the way :) unfortunately none of it worked for my XS or 12 Pro.

Below is the error message I tweeted to Apple support when iOS 14 came out. It appeared when installing iOS 14 on my old XS. Removing the passcode may not have been necessary, but after doing that I was able to install it OTA. Correlation or causation 🤷🏻‍♂️

Disable any 3rd party anti-virus software you have on your Mac or PC also!