How to fix fatal errors in Kasperksy Antivirus

Vladimir Popescu
by Vladimir Popescu
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Fatal error Kaspersky - HP laptop close-up

Some users have reported encountering the error message Fatal error inside Kaspersky. This error usually occurs during the installation process of your Kaspersky software.

This error can be extremely annoying, especially if you’ve seen it being displayed every time you want to install Kaspersky.

The Fatal error message inside Kaspersky can be caused by a conflict between a third-party antivirus software that was installed in the past on your PC, or because of the Host files that are needed to connect the Kaspersky installer to the download servers.

For these reasons, in this article, we will explore some of the best methods to apply in order to fix this issue. Please read the article carefully to avoid causing any more problems.


Try these methods to fix Kaspersky Antivirus fatal errors

1. Run SFC command inside PowerShell (Admin)

  1. Press the Win+X keys on your keyboard -> select PowerShell.
  2. Type sfc /scannow inside PowerShell -> press Enter.sfc command - Fatal error Kaspersky
  3. The process of scanning will take some time. Please make sure to wait for the process to complete.
  4. Check to see if the problem is resolved. If it is not, please follow the next method.

2. Manually uninstall any other antivirus software from your hard-drive

security - fatal error Kaspersky
There are some antivirus software options that require you to use a specialized removal tool to delete the entirety of the files.

Here are some examples:

If you’ve used any of the above-mentioned antivirus software before trying to install Kaspersky, it is recommended that you click the corresponding link above, and download the removal tool.

Follow the on-screen instructions to completely remove any trace of older antivirus software, and then try to install Kaspersky again.

If it still doesn’t work, please follow the next method.


Here’s how to fix corrupted Kaspersky databases and be protected online once again


3. Check for any leftover registry keys

Windows creates a registry key whenever you uninstall a Kaspersky product, and for some reason, this key gets forgotten by the installer when rebooting your PC to clear the files.

This registry key can cause conflicts with the new installation process of Kaspersky. In order to remove it completely, please follow these steps:

  1. Press the Win+R keys on your keyboard to open the Run dialog.
  2. Type regedit -> press Enter.regedit - Fatal error Kaspersky
  3. Navigate to the following link inside the Registry Editor window: HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
  4. Expand the folder called Run and search for a registry key called avp**_post_uninstall (Ex. avp12_post_uninstall).
  5. Right-click the above-mentioned key -> select Delete.
  6. Check to see if the issue persists.

4. Reset Hosts file to default settings to fix the Fatal error in Kaspersky

reset hosts file - Fatal error kaspersky
In order to reset the Hosts file to the default version inside Windows 10, you can visit this official Microsoft support post, and follow the on-screen instructions.


In this article, we explored some of the best troubleshooting methods for dealing with the message of Fatal error inside Kaspersky.

We would love to find out if these methods helped you solve your issue and manage to install Kaspersky Antivirus normally.

If you want to let us know, you can simply use the comment section found below this article.

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