iTunes errors when restoring, updating and synchronizing iPhone, iPod Touch and iPad (error codes, causes and solutions). iTunes errors when restoring, updating and synchronizing iPhone, iPod Touch and iPad (error codes, reasons and methods

Apple products are renowned for their reliability, but errors often occur when using iTunes. Probably every Apple gadget user has encountered this at least once. Errors can occur due to a system failure or hardware failure. iTunes error 21 is a hardware issue.

You decided to update the device system and encountered error 21. How can it manifest itself? An error message appears and the iTunes working window closes, after which it will be impossible to work in the program. After the error appeared, the computer turned off. You've received a notification that says "iTunes Error 21." The operating system on your PC runs slow when you issue commands via the mouse or when typing on the keyboard. At times the PC freezes for 3-4 seconds.

Such a failure can generate alerts not only when working in iTunes itself, but also when using components associated with it. When the PC shuts down or when it turns on, failure alerts may also appear 21. By tracking the occurrence of a failure in time, you can easily fix the problem.

Causes

This failure may occur due to incomplete installation of iTunes program components or when these files are damaged. It can occur when the registry, which is responsible for the iTunes program, is damaged. This can happen due to the installation or removal of software that works with the program.

System files or programs have been damaged by malware or viruses. Files necessary for the proper functioning of iTunes were deleted (intentionally or accidentally) by another program. The most common cause of the error is updating a jailbroken device.

How to resolve Error 21

If you need to update a jailbroken device, use DFU mode recovery using the “Redsn0w” program. Redsn0w allows you to restore any gadget from any condition. In order to resolve the failure, enter the device into DFU mode by simultaneously pressing and holding the “Home” and “Power” buttons for 10 seconds. After this, stop pressing “Power” while continuing to press “Home” until a message about emergency recovery of the gadget appears in the iTunes window.

In this case, the device display should be without images. Wait for another message “The iDevice “iDevice” could not be restored...” to appear and perform an IPSW restore. Other methods are aimed at eliminating failures in gadgets that have not been jailbroken.

Updating or installing iTunes

Check if there are updates for the program and update it to the latest version. If this doesn't help, try completely uninstalling and reinstalling it. Keep in mind that uninstalling may not remove all program components. Therefore, remove it using a special utility for complete removal. Only after this install iTunes again.

Turning off the antivirus

Virus tracking software can detect a program's actions as malicious activity and, as a result, stop the program from running using blocking tools. In order to avoid such situations, you can turn off the antivirus program while working in iTunes or eliminate failures by disabling the antivirus program after they appear.

In the future, you can add iTunes to the list of exceptions. As a result, the antivirus program will not block its activities. You can do this in the settings. Provided that this function already has activity, you need to disable network scanning.

USB cable

Failures may be caused by the use of non-original components or those that are damaged. Replace the non-original cable with an original one. If you use the supplied cable, check its integrity. Don’t neglect this little detail; using good components can extend the life of your devices and eliminate such failures.

OS update

To update the Windows 10 system, press the two keys “Win” and “I”. This combination will open the options window. Here you need to open the “update and security” section. A work area will open in front of you, where there is a “check for updates” button. Click it. If updates are found, install them.

If you are using an earlier version of Windows, open Control Panel. Here, click on “Windows Update” and check. If updates are found, install them.

DFU mode

This mode is intended for disaster recovery. It works at the hardware level, bypassing the operating system. Turn off the device completely and after a couple of minutes connect it to the PC via USB cable. Open iTunes. To enter the gadget into DFU mode, you need to hold down the “Power” button for three seconds and then also hold down the “Home” key. Keep them clamped for 10 seconds. After this time, stop pressing the “Power” button, but hold down “Home” until a notification appears in iTunes that the gadget is in emergency recovery mode. Click on the “restore” button.

Removing garbage

As you use your PC over time, it accumulates a lot of unnecessary information. It can slow down the OS and cause error 21. This occurs due to conflicts between files or when the hard drive is under heavy load. You can remove garbage using the Cleanmgr utility. It is built into the system, but has a number of disadvantages. For a more complete cleaning, it is better to use WinSweeper.

To activate the process, click “start”. Then enter "command" in the search bar. Now hold down the Shift and CTRL keys and click Enter. In the access dialog, click “yes”. A blinking cursor indicates an open black box. Type "cleanmgr" " and click Enter. In the dialog box, check the boxes in the places where you want to clean. Pressing “ok” will start the cleaning process.

You can also restore registry entries. But you shouldn’t do this yourself if you are not an expert in this matter. It is better to contact a person qualified in this field with this question, otherwise you may damage your PC and destroy it. If the methods described above do not bring results, go to a repair center to diagnose the device. Hardware repair may be required.

It may happen to you that you are trying to restore your iPhone, but no matter what you do, the iPhone will not recover because iTunes error 21 or iPhone Error 21 keeps popping up! It's like whack-a-mole, you keep trying to restore but that hellish iPhone Error 21 comes again. Typically, these errors are the result of some security software package interfering with your recovery, and this usually has an easy fix.

So here we will show you 8 different ways in which you can fix iTunes Error 21 or iPhone Error 21, restore with ease, and continue using your device!

What is iTunes Error 21 (iPhone Error 21)?

Now, before we get to the nitty-gritty of how to fix iTunes Error 21, I'm sure you should be wondering what iTunes Error 21 (iPhone Error 21) to start with, and why it has this weird Obsession with your phone! The most common cause of iTunes error 21 is that your iTunes is trying to load recovery files (.ipsw) but unfortunately is blocked from authentication. This may be due to a hardware error, or there may be a communication failure between the device and the server. However, don't worry, we'll show you how to fix this iPhone error 21 easily and effectively and get back to leading your iPhone engrossed life!

Solution 1: How to fix iTunes error 21 or iPhone error 21 without data loss

One of the biggest concerns you'll likely have when trying to recover your and trying to fix iPhone 21 errors is whether your data is safe. It's a legitimate concern as many methods out there can or will certainly result in data loss. That's why we start our list with a technique that can ensure there won't be any data loss. To ensure this, you can use a very easy to use and user friendly software called dr.fone - iOS system recovery.

Your memories and data are all precious and you should not risk them. dr.fone seems to place a lot of emphasis on data retention and as such is a recommended tool for fixing iPhone Error 21. Moreover, its user-friendliness and universal nature helps as well.

Steps to fix iTunes error 21 with dr.fone

Step 1. Select "iOS System Restore"

After launching dr.fone toolkit, you will find “iOS system recovery”. Click on it.

Step 2. Connect iPhone

Connect your iPhone via cable and let dr.fone detect it. Click the Start button to continue the process.

Important: Please note that when fixing the issue - iPhone stuck on Apple logo, the IOS operating system on your iPhone will be updated to the latest version. And if the prison device is a broken iPhone, then it will be converted back to a non-prison broken state.

Step 3. Download the firmware

dr.fone will detect your iPhone model and offer the latest iOS version for download. Just click on the "Download" link and wait for the process to complete.

Step 4. Fix iTunes Error 21

Once the download is complete, dr.fone will automatically start repairing iOS, besides this time you won't be bothered with iPhone error 21 message!

Solution 2: Restart iTunes to fix iTunes error 21

Now this is just a nominal measure that you can look at, related, how sometimes turning off, switching to the computer fixes some problems. If there is a real problem, this method will be helpless in front of it, but if the iPhone error 21 is a temporary glitch, this should take care of it. You remember how I already said that iTunes error 21 is a result of iTunes being blocked. Well, sometimes simply restarting iTunes and then starting the recovery process again may be enough to fix iTunes Error 21. So, you might want to get away with this.

Solution 3: Fix iTunes Error 21 by updating iTunes

Updates on all Apple products may be necessary as they help fix bugs and whatnot. So if you've been holding out on updating your iPhone because you have a slow network, or because your phone is jailbroken or whatever reason you might have, now is the time to update it. Get the latest version of iTunes and you may be able to fix iTunes Error 21.

How to fix iTunes error 21

Open iTunes.
Go to Menu > Help.
Select Check for Updates.

Solution 4: Turn off Anti-Virus to fix iPhone error 21

Many times, the proper functioning of some vital programs may be hampered due to anti-virus software as they may be corrupted or be compromised. In this case, turning off Anti-Virus helps to access these programs independently and, possibly, update the device.

Solution 5: Remove unnecessary USB devices

You can try to fix iPhone Error 21 by removing all unnecessary external devices from your computer, as they may have programs that get in the way of proper recovery and bring you down to iPhone Error 21.

Solution 6: Check the sensor cable

This method sounds difficult or risky. However, this is not the case, not unless you do it exactly the way it should be done. This is Sort of how to defuse a bomb, cut the wrong wire and the device goes boom! Well, not literally, but you get the picture. However, if you do it correctly, you may be able to fix iPhone Error 21. All you need to do is open the device, remove the screw that connects the battery. Unplug the device's cable and put it back together. This may help, although it seems like a rather extreme and risky measure, especially considering that you have a much more guaranteed and acceptable option in dr.fone from .

Solution 7: How to fix iTunes error 21 via recovery mode

This method involves you trying to fix iPhone Error 21 through DFU mode. DFU stands for updating the device's firmware and provides a complete iPhone recovery. Although this is guaranteed to fix iPhone Error 21, it does not guarantee that all your data will be safe. Therefore, only use this method if you have exhausted all other options. Here's how you can do it.

Fix iTunes error 21 or iPhone error 21 via recovery mode

Step 1. Place the device in DFU mode.

Step 2. Connect to iTunes.

Connect your iPhone to your computer and access iTunes.

Step 3. iTunes recovery.

Open the "Summary" tab in iTunes, and then click the "Restore" button.
After recovery, the device will restart.
When asked to "Slide install," simply follow the settings.

This solution is most likely to fix iPhone Error 21, however, as I said earlier, it restores your phone to factory settings without giving you the option to create a backup. This will result in significant data loss, unlike the dr.fone alternative.

Solution 8: Check is modified or outdated software

iTunes error 21 can be caused due to outdated or corrupt software. You may be using an old version of iTunes, in which case you should contact and update it. You may be trying to install an older version of iOS, in which case you should find the latest version and install that.

Conclusion

In listing the various methods with which you can fix iPhone Error 21, we do not discriminate-NAT between the different methods. We believe that you should have maximum decision power, so we have listed them all, along with their pros, cons, as well as risks. For example, some of the methods are significantly risky and can lead to serious data loss, some of them can even destroy your iPhone if not handled well, and most of them do not provide any guarantee of success. Therefore my personal recommendation is to go with dr.fone as it is a guarantee against all the risks I just mentioned. But hey, the choice is in your hands! We just hope you make the right call and then make a general one below so we know which method works best for you!

Specially developed by Apple to work with devices on the iOS platform, it provides Apple owners with synchronization of the device with the computer, convenient work with content and a lot of other functionality, including firmware recovery. The procedure performed using iTunes is easy to implement, but during the process unexpected problems may arise that interrupt the action. Using notifications with error codes, the program informs users about software failures or hardware problems. Error 21 in iTunes may occur when updating or restoring iPhone firmware of different versions. Messages about program failures appear for various reasons. Error 21 most often indicates mechanical damage to the device resulting from malfunctions of the modem, device battery, internal boards and other components, but it can also appear as a result of software failures during the jailbreak process. Another reason is often a low battery charge or failure.

Options to resolve error 21 in iTunes.

Despite the fact that this failure is often caused by microdamage resulting from an impact or fall, as well as other hardware faults, there are also software solutions with which the user can cope with the problem on their own.

Method 1: Update iTunes

A universal method, which often allows you to get rid of most application failures when updating or restoring an iPhone 4s and other Apple devices, in some cases also eliminates error 21. If the computer does not have the latest version of iTunes, then after updating and restarting the PC, the problem may be resolved.

Method 2: Replacing the USB cable

Sometimes error 21 can be caused by cable damage or the use of a non-original cord. But even if original equipment is used, it is necessary to inspect it for kinks, twists, oxidation and other minor defects. The correct interaction of the device with the computer largely depends on the integrity of the cable, so if any damage is found, it should be replaced with a working original cord.

Method 3. DFU mode

By activating the DFU emergency mode, you can often get rid of many failures that occur during the update and recovery process, including error code 21. For iPhone 4s and other versions, the procedure follows a similar principle. Before entering the device into DFU mode, you should turn it off completely, and then connect it to the computer using the original USB cable. Next we carry out the following actions:

Press the “Power” button and hold it for 3 seconds;
Without releasing the top power button, also press and hold “Home” for 10 seconds;
after this time, release only the “Power” button, while continuing to hold the “Home” button until iTunes detects the device in DFU mode;
After the manipulations have been carried out, the program will offer to perform the only action - restoring the iPhone. Next you need to follow the instructions on the monitor.

Method 4. Disabling the antivirus

Some antivirus programs, firewalls and other system defenders can block iTunes processes, perceiving them as virus threats, as a result of which the error that appears prevents the continuation of the procedure. You can pause the antivirus while restoring the firmware and after restarting the application, see if error 21 occurs again. If the problem is resolved, you need to add iTunes to the antivirus exclusion list, and also cancel network scanning.

Method 5: Windows Update

In rare cases, updating system components helps, for which you need to go to the Windows update and security settings and search for available updates. If they are found, it is worth installing.

Method 6: Fully charge the device's battery

When the source of the problem is the battery of an Apple device, the method of fully charging the battery often helps. Once the battery has been charged to 100%, you can try the update or restore procedure again.

Method 7: Restoring Registry Files

Restoring registry entries often helps in the fight against iTunes errors if files were damaged by viruses or accidentally deleted by conflicting programs. Microsoft's WinThruster tool will help you perform the automatic fix. The program scans and then replaces damaged files with “healthy” ones. Manually adjusting the registry is possible only if you have special skills. Self-correction without specific knowledge can significantly disrupt the operation of the system.

Method 8. Hardware solution

If none of the above methods lead to the elimination of error 21 in iTunes, most likely the problem lies in internal damage to the device. Service diagnostics will help you accurately identify hardware faults. It may be necessary to replace the battery, power controller or lower cable and it is better to entrust the matter to a specialist.

You should not solder or change elements yourself without having the appropriate skills, because one wrong action can only aggravate the situation and lead to irreparable consequences in the form of the final failure of the iPhone.

Most owners of mobile equipment, including iPhones, are well aware of and can perform the recovery and flashing procedure. Unfortunately, sometimes this process ends with the occurrence of another failure. For example, this could be an error 21 when restoring an iPhone.

I would like to immediately note that it is not always possible to correct such a problem. Unfortunately, sometimes error 21 occurs not due to a software failure, but due to a hardware failure. Naturally, in this case you will only need the help of a good specialist.

It is clear that you should contact a specialist only after you have failed to solve the problem yourself using the methods suggested below.

An attempt to solve the problem using software methods

So, if an unknown error occurs on your mobile phone, you should diagnose it. If, when you try to connect your phone to a computer or connect a charging cable, it first starts showing the Apple icon, and then, literally three seconds later, the iTunes logo and cord, then this is clearly a problem with code 21. This statement is confirmed by the black screen that appears instantly after disconnecting cable.

So, if you were unable to restore your iPhone 4s precisely because of such a problem, then it is recommended to try the following method:

You need to act in a similar way when restoring an iPhone 5.

Unfortunately, this method does not always lead to the desired result. In this case, you should do the following:

If there is no result, then, unfortunately, the problem is a hardware failure.

Hardware solution to this problem

It’s clear that you really don’t want to take your phone to the service center. Usually they charge a lot of money for repairs. Therefore, if you have some experience working with electronics, you can try to carry out the following checks:

If actions at home do not bring results, then, as much as you don’t want, you will have to take it to the workshop. In this case, there is one recommendation - try to get around as many of these service centers as possible. Sometimes this can lead to real cost savings. In one place they will quote one price, in another - two or three times lower!

Manually editing the Windows registry to remove Error 21 keys that contain errors is not recommended unless you are a PC service professional. Mistakes made when editing the registry can render your PC inoperable and cause irreparable damage to your operating system. In fact, even one comma placed in the wrong place can prevent your computer from booting!

Because of this risk, we highly recommend using a trusted registry cleaner such as WinThruster [Download] (developed by Microsoft Gold Certified Partner) to scan and repair any Error 21-related issues. Using Registry Cleaner [Download] can automate the process of finding corrupted registry entries, missing file references (such as those causing the %%error_name% error), and broken links within the registry. Before each scan, a backup copy is automatically created, allowing you to undo any changes with one click and protecting you from possible damage to your computer. The best part is that fixing registry errors [Download] can dramatically improve system speed and performance.

Warning: Unless you are an experienced PC user, we DO NOT recommend manually editing the Windows Registry. Using Registry Editor incorrectly may cause serious problems that may require you to reinstall Windows. We do not guarantee that problems resulting from incorrect use of Registry Editor can be corrected. You use Registry Editor at your own risk.

Before you manually repair the Windows registry, you need to create a backup by exporting the part of the registry associated with Error 21 (for example, iTunes):

Click on the button Begin.
Enter " command" V search bar... DON'T CLICK YET ENTER!
While holding down the keys CTRL-Shift on your keyboard, press ENTER.
A dialog box for access will be displayed.
Click Yes.
The black box opens with a blinking cursor.
Enter " regedit" and press ENTER.
In the Registry Editor, select the key associated with Error 21 (for example, iTunes) that you want to back up.
On the menu File select Export.
On the list Save to Select the folder where you want to save the iTunes key backup.
In the field File name Enter a name for the backup file, such as "iTunes backup."
Make sure the field Export range value selected Selected branch.
Click Save.
The file will be saved with extension .reg.
You now have a backup of your iTunes-related registry entry.

The following steps for manually editing the registry will not be described in this article, as they are likely to damage your system. If you would like more information about editing the registry manually, please check out the links below.