How To Fix iTunes Error 40

How To Fix iTunes Error 40 - iTunes error 20
– 40 generally occur due to a problem with the hardware or software
security issue. Sometimes, hosts file on some computers may be blocking
Apple from contacting its server in other to verify a firmware.

You will notice that whenever a restore is to be
made, Apple contact its server to verify if that IPSW is currently
being signed or not. Also it checks the integrity of the IPSW to be restored. Therefore, whenever iTunes encounter troubles in carrying out these tasks, error 40 may occur.
To solve this problem, carefully follow these steps
Environment

• Windows
  

Requirements

• Download iTunes 11
  
• iPhone USB cable in excellent condition
  

Step 1: Close all running applications on your computer
Step 2: Reboot your computer
Step 3: Stop antivirus running that may have activate firewall on your computer
Step 4: Open a folder and click on Organize at the top-left of the window
Step 5: Click Folder and Search options, click View and make sure Show hidden files folders and drives is checked.
[You must be registered and logged in to see this image.]
Step 6: Click on the windows key on the keyboard and type Notepad
Step 7: Right Click on Notepad and select Run in Administrator.
[You must be registered and logged in to see this image.]
Step 8: Click Open at the top – left window of the Notepad window. Navigate to this directory C:\Windows\System32\drivers\etc[You must be registered and logged in to see this image.]
Step 9: It may be empty, Just change the options from the box at the right side of the window from Text documents to All files
Step 10: elect hosts and it will display in the Notepad as shown in the image.[You must be registered and logged in to see this image.]
Step 11: Remove any link aside from what is in the image
Step 12: Click File, Save and exit Notepad[You must be registered and logged in to see this image.]
Step 13: Launch iTunes and then connect device with a good USB cable attached to the computer directly
Step 14: Hold Shift on the keyboard while you click Restore[You must be registered and logged in to see this image.]
Step 15: Now restore you device again using a stock IPSW and you won’t see the error anymore
Step 16: If problem persist, use another computer to perform the restore
iTunes
error 40 is fixable. All you need do is follow the instructions
carefully. Please feel free to comments on your success or where you
have issues.