Windows Security allows you to manage quarantined items and exclusions. When doing so if you receive an error saying Windows Defender Antivirus Error loading type library/DLL, Click help for more information about this problem, Error code 0x80029c4a, then this post will show you how to fix that error. Because of this error, you will not be able to see the list of quarantined and allowed items.
Windows Defender Error loading type library/DLL
If you are on the Windows 10 v 1709, you must know that what Microsoft used to call Windows Defender is now known as Windows Security. The error code seems to be occurring, according to forum users, to those who are trying to launch Windows Defender but using an old shortcut that was for Windows Defender Security Center.
Let’s be specific. When you use the old shortcut, you are launching an older version which is still supported or available on your computer.
C:\Program Files\Windows Defender\MSASCui.exe
This file is not available anymore in Windows 10 v1903.
There are two ways to fix it:
1] Run MSASCui.exe with admin privileges
- Navigate to the C:\Program Files\Windows Defender directory.
- Right-click on the MSASCui.exe and select Run as Administrator.
It will launch the Windows Defender Security Center, and you should be able to manage your quarantined list. When you upgrade to the new version of Windows, this shortcut will stop working.
2] Use the new Windows Security
- Type Windows Security in the Start
- When it appears, drag it to the desktop or right-click and add to taskbar.
- Now when you launch it, it will open the new interface, and it will work properly without any error.
This bug was identified by Microsoft as well, and one of the engineers left a comment in the Feedback Hub. It said:
This error can occur in Windows 10 Fall Creators Update (version 1709) if you are using a shortcut to open Windows Defender, and that shortcut was created while using Windows 10 version 1703. Windows Defender Antivirus had an updated experience that shipped with Windows 10 Creators Update (version 1703), which was designed to be easier to use and provide a comprehensive security experience. However, the old UI from version 1703 is no longer supported in version 1709. To resolve the error, we recommend you delete any previous shortcuts you were using launch Windows Defender and create a new shortcut within Windows 10 version 1709.
We hope the solutions worked for you, and you were able to use it again. You should upgrade your Windows 10 to the latest available version or switch to the new interface and get rid of this error.