How to Fix Windows Defender Update Fails 0x800106ba Error

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Windows Defender is a built-in Windows firewall introduced in Windows XP. When using, you may get error 0x800106ba. This means that an error occurred while trying to update the utility. This is because Windows Defender may have incorrectly saved necessary files to the operating system. There are several ways to solve this problem. This is explained below.

What are the causes of error 0x800106ba?

The error might look like this:

Error code 0x800106ba. Failed to initialize the application.


Error code 0x800106ba The system license has expired. Your connection request was rejected.

This sounds like very harmful statements about your PC. However, it is important that you are not intimidated as this is only a minor issue that will be resolved by carefully following the following steps.

Configure the Windows Defender Antivirus service to start automatically

Make sure the Windows Defender service is running. Set up automatic adjustment as described below:

  • Enter services in the Windows search and select services from the list.
  • Find Windows Defender and double click on it.
  • Select the startup type and set it to Automatic.
  • Click Apply and OK to save your changes.

Updated: July 2024

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Apply the latest Windows updates

In some cases, a simple update of Windows Defender definitions can resolve various issues with this antivirus software. Here’s how:

  • Finally, open the Settings app by pressing Windows Key + I.
  • Select Update & Security and click Check for Updates.
  • Let the system find available updates and install them all.
  • Finally, restart your system.

Use the command line.

There are several commands that you can run from the administrative command line that can help you solve this problem.

  • Click the Windows key, right-click the result, and select Run as Administrator. Or, press Windows and X on the keyboard at the same time and select Command Prompt (Administrator) from the menu.
  • From the Administrator command prompt, type the following commands and press Enter after each command to launch them. Wait for the message that the first command is complete before writing and executing the second command. Also, do not make misprints in the controls.

“% PROGRAMFILES% \ Windows Protector \ MPCMDRUN.exe” -RemoveDefinitions -All

“% PROGRAMFILES% \ Windows Protector \ MPCMDRUN.exe” -SignatureUpdate

After executing both commands, you can close the command line.

Try to run the updates now. You can do this through the Windows Update Center and Windows Protector.

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