For many of you who have iPhone 4′s and tried to update to iOS 4.2.1, you may encounter Error 1013 on iTunes. This seems to be a widespread issue and widely discussed on Apples forum. Fear not, there is already a way to fix this Error 1013. Due to the rush of releasing this iOS version, a bug like this is bound to come out. This has been reported to Apple but if you dont intend to wait any longer, please see the following for the instructions. Methods on Fixing the Error 1013 are available for Mac and PC. Mac OS X 1. On your Mac, go to Applications folder. 2. Go to the Utilities folder. 3. Start Terminal. 4. Type sudo nano /etc/hosts (without quotes) and hit enter. 5. Enter your login password 6. Use the down arrow key to find gs.apple.com. Add # in front of the text e.g. #gs.apple.com 7. Save the file by hitting CONTROL+O. 8. Exit the nano editor. 9. Restore your iPhone. Windows 1. Go to Start > Programs > Accessories 2. Run Notepad. Note: on Windows 7, right click on Notepad icon and select Run As Administrator 3. Click File > Open 4. Go to Windows/System32/drivers/etc 5. In files of type: select all documents 6. Open hosts 7. Delete any entry with gs.apple.com 8. Click Save 9. Restore your iPhone Good luck!!!