Why am i seeing the Error 21 message when i try to restore my iPhone 4?

Question

Level 1

0 points

Why am i seeing the Error 21 message when i try to restore my iPhone 4?

My iPhone 4 wasn't charging so I had the battery changed and then the charging unit. Then the Apple sign just kept flashing on and off when I plugged it in to charge so I put it into restore mode. But every time I try and restore it in iTunes I get the Error 21 message, I have tried endless suggestions such as updating iTunes, trying to put the phone into DFU mode, disabling security software, and others I now can't recall as it has all sent my head quite fuzzy during this 4-hour ordeal! But nothing seems to work. Does anyone know what could be the problem?

iPhone 4

Posted on Sep 9, 2013 3:03 PM

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Answer 1

pvonk

Level 6

13,851 points

Sep 9, 2013 3:07 PM in response to becky161

Well, you've listed many of the suggestions given in the past. All I can add is to go to the search bar above to the right and enter "error 21" (without quotes) and begin to search through the hits.

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Answer 2

Sep 9, 2013 3:10 PM in response to becky161

Probably an issue with security software on your computer. Read this article: http://support.apple.com/kb/TS3125

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Answer 3

Clyde77

Level 4

2,789 points

Sep 9, 2013 3:12 PM in response to becky161

first try a different usb cable, remove all other usb devices, and try a different port in back on desktops if possible. if no luck see these

These errors typically occur when security software interferes with the restore and update process. FollowTroubleshooting security software issues to resolve this issue. In rare cases, these errors may be a hardware issue. If the errors persist on another computer, the device may need service.

Also, check your hosts file to verify that it's not blocking iTunes from communicating with the update server. See iTunes: Advanced iTunes Store troubleshooting—follow steps under the heading Blocked by configuration (Mac OS X / Windows) > Rebuild network information > Mac OS X > The hosts file may also be blocking the iTunes Store. If you have software used to perform unauthorized modifications to the iOS device, uninstall this software prior to editing the hosts file to prevent that software from automatically modifying the hosts file again on restart.

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Answer 4

ChrisJ4203

Level 10

230,347 points

Sep 9, 2013 4:33 PM in response to becky161

According to this support document http://support.apple.com/kb/TS3694, which is partially quoted above, try what Clyde77 posted.

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