Windows Defender - Virus and spyware definitions couldn't be updated

Kan de spyware- en virus-definitie niet bijwerken.

can't update spyware and wirus definition

I Can't updatge Defender spyware and virus definitions

I Can't updatge Defender spyware and virus definitions

REPOSTING

When did Windows Defender (WD) update? What virus definitions are currently installed? https://www.microsoft.com/en-us/wdsi/definitions/antimalware-definition-release-notes  

See Troubleshoot Windows Defender Update Issues in Windows 10

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

See the Answer of quietman7 - MVP  in https://answers.microsoft.com/en-us/protect/forum/protect_defender-protect_updating/windowsdefender-wont-turn-on/c502c63f-2ffe-4cfd-8b6b-bdfd086cfae0

If the issue continues you may want to try the steps recommended in Problems starting Windows Defender in Windows 8/8.1/10 to include (but not necessarily limited to) running SFC, scanning for malware and running the software removal tools for any security software (AVG, Kaspersky, McAfee, Norton, whatever) that may have previously been on the computer (to include a trial version of McAfee or Norton that might have been on the computer when it was new) followed by a reboot:  List of anti-malware product removal tools

You might also want to review http://www.howtogeek.com/220232/how-to-use-the-built-in-windows-defender-antivirus-on-windows-10/   Good article but ignore the ads!

Or

If WD still does not update, wait a few hours and try again to manually update the program….remember WD normally should automatically update every 24 hrs if an update is available and the program needs to be updated. 

Alternatively - - -

You may prefer to install a third party antimalware program (which should disable Windows Defender).

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://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/