Fix Windows Defender Error Code 0x800106ba

One of the following error messages may display on your screen when you attempt to run Windows Defender on your computer:

Error Code 0x800106ba Application failed to initialize

Error Code 0x800106ba The systems license has expired. Your logon request is denied.

Cause of the Error

This error message appears when your system encounters a problem while the Windows Defender utility is being updated.

Resolution Method

To resolve the issue, you need to first uninstall and then reinstall Windows Defender on your system. The steps to do this are discussed below:

Step 1: Uninstall Windows Defender Using the Add or Remove Programs utility.

  1. Open Start menu, select Run, type appwiz.cpl and then press Enter.
  2. Next, from the Currently installed programs list, select Windows Defender.
  3. Click Remove.
  4. Follow the onscreen instructions to remove Windows Defender from your system.
  5. Restart the PC.
  6. Note: It is recommended that you use a reliable registry cleaner tool such as RegServe to clean your registry after you uninstall Windows Defender. This will help you ensure that no orphan Windows Defender entries are left behind in the registry.

  7. After the system restarts, visit the Microsoft Windows Defender website, download Windows Defender again, and then install it on your system.
  8. Try to update from the Windows Website and check to see if the error goes away.

If the error still exists, proceed to the next step.

Step 2: Uninstall Windows Defender using Windows Installer Cleanup Utility

Windows Installer Cleanup utility can be used to remove the Windows Installer configuration files and registry entries of a program that was installed using the installer.

Note: You cannot use this utility to uninstall Windows Installer or remove installation files of programs installed using the installer.

To use Windows Installer to remove installer configuration files of Windows Defender, perform the following steps:

  1. Use the Add or Remove Programs utility to remove Windows Defender. (as described in step 1)
  2. Download Windows Installer Cleanup utility from Microsoft Web site.
  3. Install the utility on the system and then run it.
  4. Choose Windows Defender from the list displayed and clean its Windows Installer configuration information.
  5. Visit the Microsoft Windows Defender website, download Windows Defender again, and then install it on your system.
  6. Try to update Windows Website and check to see if the error goes away.

If the error still exists, proceed to the next step.

Note: To ensure complete removal of the program, you may also opt to use a third-party Windows Uninstaller tool, such as Perfect Uninstaller to uninstall Windows Defender.

Step 3: Reregister Windows Defender DLL Files on the system.

  1. Open Start menu, select Run.
  2. Next, type the regsvr32 file_name command and then press OK to register the following files on your computer.
    • wuapi.dll
    • wuaueng.dll
    • wucltui.dll
    • wups.dll
    • wuweb.dll
    • atl.dll
    • softpub.dll
    • wintrust.dll
    • initpki.dll
    • mssip32.dll

Registry problems are one of the major causes of errors such as error Code 0x800106ba. This is the reason why, it is recommended that you regularly scan and clean your registry with the help of a reliable registry cleaner tool to maintain a healthy error-free computer for a long time.