Norton antivirus is a software which is developed by Symantec 28 years ago in 1991 as a security product. It secures your device from all the mischievous malware, spyware, viruses and other online threats. Not only it saves your computer or laptop but also your smartphones from hacking so that no one can sneak into your private photos or whatever information you stored in it. Their “cloud-based technology” is the main reason behind the safety of your device and your personal information. If you want to secure your data, then Norton.com/setup is the best option you take for remarkable security of you and your data from the hackers or cyber criminals.

Different methods to resolve Norton Error Code 8504.421

Symptoms of Error 8504.421

  • The error appears from nowhere and crashes the all active program windows.
  • In a repeatedly mode your computer freezes for a few seconds.
  • Your system windows will run slowly and, it also affects the responding of mouse and keyboard inputs.
  • Most commonly Norton error 8504,421 is displayed on your screen from time to time.


Causes of Error 8504.421 

  • Your windows system files have corrupted because of viruses or malware.
  • By mistake deletion of Norton related antivirus program.
  • Incomplete installation of Norton antivirus software in your PC.
  • Downloaded a corrupted file.

Different methods to resolve Norton Error Code 8504.421 

Method1: Attempt offline service of “Windows Update.”

For updating of windows operating system (7,8,10, XP and Vista) steps are mentioned below.

  • Click on the “start” taskbar button.
  • Enter “update” in the search bar.
  • Subsequently, windows update dialog box will come up.
  • If you notice any new update of the window then press the “install updates” button.

Method2: Setup “Windows System Restore” 

  • Press the “start” button on the lower left side of your screen.
  • Type the “system restore” in the search bar.
  • Few result searches will come to your screen.
  • You have to click on the “system restore.”
  • Sometimes you have to enter your administrator password.
  • Now you have to follow all the steps one-by-one.
  • Choose a suitable restore point.
  • At last, restore your PC.

Method3: Uninstall and again Install your Norton tool 

  • Hit on the “start button” to open up the “programs and features.”
  • At the right corner, menu presses the “control panel.”
  • Click on the “programs.”
  • You need to click on “programs and features.”
  • In your system trace the error related program.
  • You need to press on the Norton antivirus related entry.
  • Hit on the uninstall button at the upper menu.
  • One-by-one follow the rest of the steps displayed on your screen.

Method4: Scan down your device 

  • Press the “start” button and enter “command” in the given area of the search box.
  • Together with Ctrl-Shift key, you have to press Enter key.
  • Approval window will emerge on your screen.
  • Hit the “Yes” button.
  • With a sparkling cursor you will get the command prompt window.
  • Now enter the SFC/scan now command to complete the process.


Norton antivirus software comes in different range according to your need. The regular updating of our software is the reason why everyone put their trust in us for the safety of their data or information.

  Modified On Jul-19-2019 09:38:36 PM

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