Every so often I note that Windows Defender reports that "you have not
scanned in three days."
Yet Defender is correctly configured to scan daily, is set to start up
on boot, and is verified as running. Nonetheless, the applet for
Security Center|Malware Protection reports that "W.D. is turned off."
When the "turn on now" button is clicked, a lengthy search is made for a
new definition - which usually results in none being found - and the
"turned off" notice remains.
Defender runs manually, if initiated. Can others confirm this behavior?