By Dylan / Last Updated April 28, 2021

Scenario

Can't update iPhone error 4000

I connected iPhone 12 to iTunes and there was an available iOS 14.5 update that had been downloaded. I clicked Update but after a while, it reported: can't update iPhone error 4000. How can I solve the problem and update my iPhone now?

- Question from Apple Community

Apple usually pushes update for iPhone users to introduce new features and fix the bugs in the present iOS.

Updating an iPhone is necessary because new iOS like iOS 14.5 give users more features. However, it is not always easy. The process might fail even if you have downloaded the installation package in iTunes. If you see the error message that The iPhone Could not be Updated. An Unknown Error Occurred (4000), just follow this passage to know why it happens and how to solve it.

Error 4000

Why iPhone saying error 4000 when updating?

Generally speaking, there could be 3 possible reasons causing iOS updating failure:

iOS has been updated on iPhone. Sometimes, the OS can be updated with the latest iTunes software, so you can't run the update program.
Low battery: The iOS update program wouldn't run if your battery level is lower than 50%.
Not enough space on your iPhone: New iOS system can take several GB of space. If your iPhone is running out of space, you can encounter "Can't update iPhone error 4000".
The iPhone is locked. A locked iPhone can't perform a system update.
iTunes version is old. Sometimes, an outdated version of iTunes software can trigger iOS failure.

So next, this post will list several fixes according to the causes above to help you out of the issue.

How to fix "can't update iPhone error 4000" on iTunes with 7 methods ?

First of all, you need to make sure your iPhone battery level is higher than 50%. And also, you can try restarting the update program to see if it works. Then try the following solutions below.

Method 1. Check the iOS version on the iPhone

The present iOS on iPhone might be newer than the iOS on iTunes.

You need to go to "iPhone Settings" > "General" Then check the software version.

If you have iOS 12.4.4, you cannot use the update of iOS 12.4.3 in iTunes. However, you would find a way to install an old version of iOS in the last section of this passage.

Method 2. Update iOS on the iPhone

Meanwhile, you could check whether there is an available iOS update for iPhone to update iOS on iPhone.

Go to "iPhone Settings" >"General"> "Software Update".

It is suggested to backup your iPhone before you install the latest iOS because updating the iPhone could not only solving the previous problems but also bring new problems.

iOS Software Update

Method 3. Keep iTunes up-to-date

Old iTunes could not be used to update iPhone and often reports error. You need the latest iTunes on PC.

You need to click "Help" in iTunes and then select Check for Updates.

iTunes Check For Updates

Method 4. Keep iPhone screen unlocked

iTunes can’t import data to iPhone because of privacy issues. You need to unlock iPhone screen when you transfer data between iPhone and computer.

Go to iPhone "Settings" > select "Display & Brightness" > select"Auto-Lock" > check "Never".

Display Brightness

Method 5. Manually update iPhone iTunes

If you click Update in iTunes but get error 4000, you could try manually update iPhone in iTunes.

1. Connect iPhone to computer with USB cable. Click the device icon and then select Summary section.

2. Make sure you have downloaded the latest iOS update in iTunes. You can find it in C: \Users\User Name\AppData\Roaming\Apple Computer\iTunes\iPhone Software Update. If you haven’t downloaded the right version of iOS in iTunes. Go to https://ipsw.me/ to download the firmware to computer.

3. Press and hold the "SHFIT“ Key and click Update in iTunes.

4. Select the iOS update from your computer and open it to install the latest iOS.

Method 6. Enter Recovery Mode to update iPhone

If iPhone still could not be updated for error 4000 after you try every method, there is the ultimate way. It is proved that updating iPhone could be successful after Recovery Mode.

You need to know that putting iPhone into Recovery Mode might make you lose all the data on iPhone, so it is very necessary to backup important data before you execute this method. Clicking Update is safe but doesn't click Restore.

1. Put iPhone into Recovery Mode.

There are different operations for different iPhones. Connect your iPhone to iTunes with a USB cable and pick the right method for your iPhone to enter Recovery Mode.

iPhone 8 or later: Press the "volume+" button and then quickly release. Press the volume- button and then quickly release it. Press the "power" button for seconds and then iPhone would enter recovery mode.
iPhone 7 and iPhone 7 Plus: Press both the power button and "volume-" button for seconds and the iPhone would enter recovery mode.
iPhone 6s or earlier: Press both the power button and the "Home button" for seconds and then iPhone would enter recovery mode.

2. You could see the pop-up below in iTunes and click Update.

iTunes Repair iPhone Recover Mode

Method 7. Free up iPhone storage

If your iPhone storage is full, iPhone won't update, and iTunes may prompt you "Can't update iPhone Error 4000". You can go "setting" > "iPhone Storage" to see what files are taking up your storage space.

Firstly you can enable "Optimize Photos" and "Offload Unused Apps" to release some space.

✍Note:
Offload Unused Apps: This feature will automatically offload unused apps when your iPhone is low on storage.
Optimize Photos: Full resolutions photos will be kept in your iCloud storage, and your iPhone will store a compressed version.

If your iPhone storage is still not enough, you can back up your important data to a computer or external hard drive and delete them to free up more space.

You can turn to AOMEI MBackupper which is a brilliant professional iPhone backup software. You can use it to save photos, videos, music, contacts, and messages from iPhone to a PC. What's more, you could use this software to directly import photos from PC to iPhone. It is better than iTunes because photos synced from iTunes will be removed if you enable iCloud photos on your iPhone.

  • Totally Free: Backup and restore unlimited iPhone with AOMEI MBackupper.

  • Select Data: Preview and select all the items you need from iPhone.

  • Incremental Backup: Backup iPhone in a professional way to save time and space.

  • Widely Compatible: Backup any iPhone with AOMEI MBackupper, including iPhone 12/SE 2020.

Download AOMEI MBackupper to computer and follow the steps to easily backup your iPhone:

Step 1. Connect iPhone to computer with USB cable and select Custom Backup.

Custom Backup iPhone

Step 2. Click the icon of every feature to preview and select iPhone data. Click OK to return.

Select iPhone Data

Step 3. Click Start Backup to quick save everything you select.

Click Start Backup

When the backing up process is completed, you can delete large apps, photos, videos to free up space, and continue to update iOS

Bonus Tips: How to install previous iOS?

What if you don’t like the present iOS on iPhone? In fact, you could install any version of iOS by yourself. Before you downgrade iOS, remember to backup iPhone because downgrading iOS would factory reset iPhone.

1. Go to ipsw.com to download the right installation package of iOS to computer.

2. Connect iPhone to iTunes and click the device icon.

3. Press and hold the SHIFT key and click Restore iPhone.

4. Select the folder you have downloaded to reinstall the iOS.

Downgrade iOS 14 to iOS 13 via iTunes

Conclusion

This is all about how to fix "can't update iPhone error 4000" on iTunes with 7 methods. If you have problem that you can’t update your iPhone. You could follow this guide to know why you can’t use iTunes to update your iPhone.

Besides helping you solve this issue, this guide also provides useful tips for you to backup iPhone and install previous iOS. To protect iPhone data, you need to use AOMEI MBackupper to backup iPhone regularly.

Don't forget to share this guide to help more people.