Question How often should we do a Quick Scan and a Full Scan?

With Defender, why is a manually invoked or scheduled scan, actually needed?

Unless you made pains to not have this happen, it runs in the background.

Download something, and it wakes up and scans.
Try to install something, it scans and checks.
 
My apologies. Where this was a fairly easy process within W10, it appears that W11 and/or some update have done away with this option. It appears you have to use Task Scheduler to set something up at this point.
seems those steps apply to win 10 as well unless Microsoft are stupid and labelled this page wrong - https://support.microsoft.com/en-us...ntivirus-54b64e9c-880a-c6b6-2416-0eb330ed5d2d
thats dumb, why bury it? Normal users have no clue what Task Scheduler does or that it even exists.
 
For the past few days, I noticed that when I used Quick Scan built in Windows 10, there is a list of "Threat blocked" (Severe) under Protection history. Do I need to worry about it?

When I clicked on any of those Severe, a window showed up saying: Windows Security Do you want to allow this app to make changes to your device.
What is that for? Shall I click Yes or just close the window?
 
For the past few days, I noticed that when I used Quick Scan built in Windows 10, there is a list of "Threat blocked" (Severe) under Protection history. Do I need to worry about it?

When I clicked on any of those Severe, a window showed up saying: Windows Security Do you want to allow this app to make changes to your device.
What is that for? Shall I click Yes or just close the window?
For the last few days, Win Defender has been showing a false pos.

https://www.windowscentral.com/soft...orwin32hivezy-its-nothing-to-be-worried-about