Hello to all,
I was just wondering about what is error 21 on itunes. Every time I try to read about it, I fail to understand the same.
Is there anyone who can help me?
If you are jail breaking your iPhone, iPod or iPod Touch by using custom IPSW by PwnageTool or Sn0w breeze, then it will require a full firmware restore while using iTunes. During the process, if Error 21 pops up on the screen, then that means that you are attempting to restore using the recovery mode. To resolve this issue, you should put your iDevice into DFU mode.
Error 21 in iTunes is related to hardware problem. If you need to use iTunes and you receive this error, here’s how to check. First, download the latest iTunes and install it. Once your iTunes is updated, start iTunes. If you receive the error again, restart iTunes. If iTunes is currently open, close iTunes and open it again. See if it works.
If this doesn’t work, check your security software. Try disabling your antivirus or firewall temporarily then start iTunes. See if it works. If it works, add iTunes to your security program’s exclusions list. In your antivirus, go to “Settings” then expand the “Real-time protection” item. Look for something like “Exclusions” or something similar and select it.
Click “Add” then navigate to the installation folder of iTunes and select the main EXE file. This should fix the problem once the file is added to the exclusions list. You may now enable your antivirus back. On the other hand, if disabling your antivirus doesn’t work, make sure your USB cable is working.
Use a different USB cable to connect your iOS device to your computer and try again. Also, try transferring your USB cable to another USB port.
