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I keep getting 'Unknown Error occurred 21' while trying to restore iPhone 4

2012-04-22 17:45:07Reply this question Reply Topic
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I keep getting 'Unknown Error occurred 21' while trying to restore iPhone 4

It started with the apple logo just flashing on and off. So I went to reset my daughters iPhone by pressing the on/off button and the menu button simultaneously until the iTunes logo and the USB cable was shown on the screen. At that point, iTunes wrote;

 

'iTunes has detected an iPhone in recovery mode. You must restore this iPhone before it can be used with iTunes.

 

I clicked 'OK' and then 'Restore'. ITunes then went on by 'extracting software...' for a minute or two and then 'Preparing iPhone for restore...'  The apple logo was then shown on the iPhone and a message box i iTunes;

 

'The iPhone 'iPhone' could not be restored. An unknown error occurred (21)'

The message box leads to 'More Information' that says that the error 21 ' typically occur when security software interferes with the restore and update process'

 

 

 

That's it. I have tried everything. (I think);

 

Checking for iTunes updates

Checking for OS (Win7) updates

Restarting the computer

Changed the USB cable

Changed the computer

Ensuring that I have administrator privileges and that iTunes has it as well.

Disabling the antivirus

Disabling the firewall

 

If you have any advice, please let me know.

 

Regards

Torben Busk


Answer
2012-04-22 17:45:07

I keep getting 'Unknown Error occurred 21' while trying to restore iPhone 4

Have you tried the steps here?

TS3125 will help with anything security related.

If none of the steps work, i'd recommend reinstalling iTunes.

Removing and reinstalling iTunes, QuickTime, and other software components for Windows Vista or Windows 7.


Answer this questions Reply


Answer
2012-04-22 17:45:07

I keep getting 'Unknown Error occurred 21' while trying to restore iPhone 4

Have you tried the steps here?

TS3125 will help with anything security related.

If none of the steps work, i'd recommend reinstalling iTunes.

Removing and reinstalling iTunes, QuickTime, and other software components for Windows Vista or Windows 7.


Answer this questions Reply


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