How To Fix The Norton Error 8506 And 421?

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Norton antivirus program is a crucial part of the security system of a computer against viruses and malware. This program helps the users to monitor Internet traffic and the processes of other software to keep the computer safe. 

Despite being a popular antivirus program, users often come across the Norton error 8506 and 421 while trying to install a software or program. According to some users, they encounter this error during the Windows shutdown or startup process. 

So, if you are stuck with the same error and if you are unaware of how to resolve it, then try out the solutions described below.

What Causes the Norton Error 8506 and 421?

The Norton internet security error 8506 and 421 might trigger up for a number of reasons. Corrupt or incomplete installation of the Norton antivirus program are also the leading factor of this error. 

If the registry entries that are related to the Norton antivirus program gets damaged or corrupted, you might come across this error. Sometimes, the system files of the computer get attacked by the malware or virus and as a result, the error might pop up on the screen. 

If any of the Norton related files deleted by another software, then it might be the reason behind this error. No matter whatever the reason is, you have to troubleshoot this error immediately to get back the security system of the computer. 

Norton 360 Error 8506 and 421 on Windows 7 [2+2 Easy Hacks]:

There are several ways to troubleshoot this error. Here, we are going to discuss some of them. Hence, you can perform the methods described below: 

Method 1: Repair the Registry Entries

You can solve this error by repairing the registry entries of the computer. Hence, you need to be careful while editing the registry entries, a small mistake might lead to serious damage to your computer. 

How to Repair the Registry Entries on Windows 7? 

To repair the registry entries, navigate to the Start menu and type “command prompt” in the search bar. Once it shows the ‘Command Prompt’ option as the search result, right-click on it. 

Next, choose the ‘Run as administrator’ option from the list. 

Now, type “regedit” in the command line and then hit the Enter key from the keyboard to execute the command. Afterward, select the portion that you want to back up from the ‘Registry Editor’ window. Next, navigate to the File tab and then choose the ‘Export option from the list. 

After that, choose the folder from the ‘Save in’ option where you wish to save the backup file of the Norton antivirus program. Now, change the name of the file to ‘Norton 360 backup’. Then, click on the ‘Selected Branch’ option from the ‘Export Range’ pop-up box. 

Then, tap on the Save button to save the ‘.reg’ file extension. Now, you have successfully created a backup of the registry file of your computer. 

After doing this, you have to edit the registries to repair them. To do this, you can follow the steps given below: 

  1. First of all, find the key that you wish to edit. Then, press the F and Ctrl key both at the same time from the keyboard to open the Find dialog. 
  2. Now, type the name of the key and then tap on the ‘Find Next’ button. 
  3. Click twice on the key that you want in the list. 
  4. Afterward, edit the value data of the key. 
  5. Lastly, tap on the OK button to apply the changes and restart the computer so that the changes can take effect. 

After applying the above steps, if you notice that the error still appears, then you can move on to the other alternative ways described below. 

Method 2: Remove the Junk files of the System

Every computer accumulates junk files due to the high usage of the system and internet surfing. If those files are not cleared regularly, then it might trigger the Norton antivirus program to respond slowly. 

Hence, you can clear the junk files of the system to get rid of this error correctly. To do this, you can use the Disk Cleanup utility. Here are the steps that you can perform to clear the junk files of the computer: 

  1. In the beginning, go to the Start menu. 
  2. Then, navigate to the ‘Computer’ section. 
  3. Right-click on the main hard drive (usually it id C: drive). 
  4. Afterward, choose the ‘Properties’ option from the list. 
  5. Next, tap on the ‘Disk Cleanup’ option. 
  6. On the next screen, you will notice the list of some items that can be removed. 
  7. Select all the items and right-click on them. 
  8. Choose the ‘Remove’ option from the list. 

If you want to clear more junk files, tap on the ‘Clear up system files’ option. Select the categories that you want to remove. Then, tap on the OK button and then click on the ‘Delete Files’ option to complete the process. 

Now, check if the error is resolved. Otherwise, move on to the other ways that are described below. 

Method 3: Update the Video Graphics Driver

According to some tech experts, you can resolve the Norton error 8506 and 421 by updating the video graphic driver of the system. To do this, you can perform the following: 

  1. At first, go to the Start menu and then type “device manager” in the search bar. Then, hit the Enter key to open it. 
  2. Click on the ‘Display adapters’ option to expand it. 
  3. Now, right-click on the ‘HD graphics card’ and choose the ‘Properties’ option from the list. 
  4. Afterward, go to the Drivers tab to check for the available updates. 
  5. In case you see there is available any latest updates, download and install that by following the on-screen guidance. 
  6. Once you complete the updating process, restart the system to apply the changes. 

Now, you can check if the error has been fixed. Else, you can perform the next method to get rid of this error. 

Method 4: Reinstall the Norton Antivirus

If all the above hacks failed to solve this error, you can replace the old version with the latest one. To do this, you can use the ‘Norton Remove and Reinstall’ tool. To do this, apply these steps: 

  • First, visit the official website of Norton and then download the ‘Norton Remove and Reinstall’ tool. Save the file on the Windows desktop. On some browsers, the file is stored automatically to its default location. 
  • Press the J and Ctrl key simultaneously from the keyboard to open the Downloads window of the browser. 
  • Click twice on the NRnR icon. 
  • Read the license agreement carefully and tap on the Agree button. 
  • Tap on the ‘Remove & Reinstall’ option. 
  • Confirm the action by clicking on the Remove or Continue button. 
  • Lastly, tap on the ‘Restart Now’ option to apply the changes. 

After reinstalling the Norton antivirus program, you will not notice the Norton error 8506 and 421 further as expected. 

Hopefully, the above hacks will help you to put an end to this error.