windows defender cannot update with error 8024401b

cannot update my defender cause of error 8024401b

Restart the computer – sometimes that will clear the error.

What virus definitions are installed in WD? 

When did WD last install updates?

 https://www.microsoft.com/security/portal/definitions/whatsnew.aspx

This may be a transient error involving the update servers – unless the issue continues for at least another 24 hrs I don’t think I’d be overly concerned as long as WD is working okay.  You might test WD by downloading the Eicar Test File: http://www.rexswain.com/eicar.html

Any other security program installed?

The behavior you are describing may occasionally occur if there are remnants of a third party antivirus program still installed.  

Go to Security and Maintenance, look in 'Security' and see what program is listed under Virus Protection.  Windows Defender will not be enabled and functioning properly if there is a program other than Windows Defender listed.

Have you tried the steps recommended in Problems starting Windows Defender in Windows 8/8.1/10 to include running SFC, scanning for malware with Malwarebytes and running the software removal tools for any security software (AVG, McAfee, Norton, whatever) that may have previously been on the computer followed by a reboot? List of anti-malware product removal tools

Or

If that doesn’t work, wait a few hours and try again….remember WD normally will autoupdate every 24 hrs as needed.

And you can always try resetting Windows Updates: 

https://support.microsoft.com/en-us/help/971058/how-do-i-reset-windows-update-components

Alternatively - - -

You may prefer to install a third party antimalware program (which should disable Windows Defender) and you’ll no longer be concerned with the various issues that intermittently affect Windows Defender on Win 10.

There are a number of viable free and paid options available – take your pick…

Choosing an Anti-Virus Program

Is Windows Defender The Best For Windows 10?  Good article but ignore the ads.

http://www.dslreports.com/forum/r30380692-AV-Poll-2015

http://windows.microsoft.com/en-US/windows/antivirus-partners#AVtabs=win10

Regards…

http://blog.emsisoft.com/2015/01/27/top-10-ways-pups-sneak-onto-your-computer-and-how-to-avoid-them/