Posted by Aimee , Jan 18, 2019
"The iPhone could not be restored. An unknown error occurred(21)."
To most iPhone users, it's so scary to see such message popping up. But it does occur when you try to restore or upgrade your iPhone. So what should we do to conquer it?
Today in this post, we will show you several ways to get iTunes error 21 fixed.
Method 1: Update the version of iTunes to the latest one.
Method 2: Turn off Anti-Virus.
Method 3: Remove Host File. Navigate to C: /window/system32/drivers/etc/host. Move host file to desktop or somewhere you can find them, Try to restore your iPhone again. If you have successfully restored your iPhone, please remove host file back.
Method 4: Restore iDevice by Recovery Mode, but please note that it could cause data loss.
So is there a better solution to fix iTunes error 21? Absolutely yes! RecoveryTool Fix Recovery could be your best choice. It can not only fix your issue quickly and efficiently. Furthermore, it won't cause any data loss.
Step 1: Download, launch and run the software on your PC. Then select "Repair".
Step 2: Now please connect your iPhone to your PC via USB cable. Once the program detects it, tap on "Start" to continue.
Step 3: The software will identify the iPhone model and then offer the newest iOS version for you to download. Simply tap on "Download".
Step 4: Once the download is OK, it will start repairing the iOS automatically.
See, quite simple, isn't it? With the help of RecoveryTool, you can fix the iTunes error 21 with ease without worrying about the loss of your precious data. Come on for a try!