Windows Defender Error “Unexpected error. Sorry, we ran into a problem. Please try again”

Since the latest Windows 10 Creators Update, I have been seeing some issue with Windows Defender alerting me that it cannot start. When I try to start the service, I get the following error:

Unexpected error. Sorry, we ran into a problem. Please try again

 

The trick was to edit some registry settings (of course).Open Registry Editor and go to:
HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows Defender

Change DisableAntiSpyware and DisableAntiVirus values from 1 to 0

Coincidentally, I didn’t have an entry for DisableAntiVirus and had to create it