Windows Defender is a free antivirus software from Microsoft. The program is well known for its reliability, effectiveness, and stability but, occasionally Windows Defender or Microsoft Security Essentials might turn nonfunctional, displaying this Microsoft Defender error code 0x800106ba with a short description – Windows Defender application failed to initialize.
Error Code 0x800106ba, Windows Defender Application failed to initialize
Why does this problem arise? Well, some third-party software installations cause a conflict with Windows Defender. Running two security software can also create such problems. Sometimes, the DLL files from the utility are not registered properly. They too can cause the problem.
To fix this issue, you can try the following:
1] Check Windows Defender service status
Run services.msc to open the Services Manager and ensure that the following Services show this status:
- Windows Defender Firewall – Automatic | Started
- Windows Defender Advanced Threat Protection – Manual
- Microsoft Defender Antivirus Network Inspection Service – Manual
- Microsoft Defender Antivirus Service – Manual.
2] Re-register Windows Defender DLL files
You have to re-register each of these dll files. So for each of these files, replace “file name” with each one of these, one after the other and hit Enter:
regsvr32 wuaueng.dll regsvr32 wucltui.dll regsvr32 softpub.dll regsvr32 wintrust.dll regsvr32 initpki.dll regsvr32 wups.dll regsvr32 wuweb.dll regsvr32 atl.dll regsvr32 mssip32.dll
Restart and see if it has helped you.
If you wish, you may download and use our portable FixWin to reset Microsoft Defender settings to default.
You will find the setting under AdditionalFixes > Quick Fixes > Reset Windows Defender Settings.
You may also see if this Microsoft Fix It 9779673 helps you.
Windows Defender is turned off or not working may also interest you.