[7 Methods]How to Fix Can’t Update iPhone Error 4000 in iTunes

Scenario

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 gives 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.

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 Sometimes, an outdated version of iTunes software can trigger iOS failure.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

• Method 2. Update iOS on the iPhone

• Method 3. Keep iTunes up-to-date

• Method 4. Keep iPhone screen locked

• Method 5. Manually update iPhone iTunes

• Method 6. Enter Recovery mode to update iPhone

• Method 7. Free up iPhone storage

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 the latest iOS, you cannot use the update of old iOS version 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.

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.

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".

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.

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 FoneBackup 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.

• Fast backup: It will backup your iPhone with fast speed.

• Backup all iPhone data or select items: You can backup all data on your iPhone or select some items you need to backup.

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

• Widely Compatible: Backup any iPhone with AOMEI FoneBackup, including the newest iPhone model.

Download AOMEI FoneBackup to computer. Then we will guide you on how to backup your all iPhone data:

Step 1. Connect iPhone to computer with USB cable > Click Phone Backup and get to Full Backup. If you just want to backup some items, please choose "Selective Backup".

Step 2. Click Get Started icon below Full Backup pane.

Step 3. Here you can encrypt the backup, and choose a location to save the back files. Then click Start Backup to quickly save everything you select.

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.

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 FoneBackup to backup iPhone regularly.