Windows 10 - Defender Offline Scan not working

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OK. I'm gonna rush in here where angels get a clump on the head and ask a stupid question:

Y'all realize that you have to be on-line in order to start Windows Defender's Off-line Scan, yes?

Hi Cass,

Your question is not stupid, but very astute. The first thing WDO does (or should do)

is download the latest definitions. That would be considered to be "Online". However,

the WDO program should be booted into the machine. That puts the machine

"Offline". Offline, in this case, meaning that the operating system is not loaded, and

any malware within it can have no effect on the scan.

That is how it's supposed to work!     It is not working that way right now!

The observable symptom is;  Once WDO is started the machine boots. The "splash" 

screen is displayed for about two minutes, then the machine boots back to Windows.

No scan takes place ! 

I believe that the cause for this problem has been defined already, in this thread.

Those, from Microsoft, who could have some effect on its resolution, have barely

missed the post. It has been obscured, in this thread, and in another thread. I fear if

I describe it here, it will not be seen either. I will start another thread to describe it.

What John Q has discovered is, that some Microsoft Updates are causing the problem.

Regards,  Glen

Thanks. Thought so. Uh...it works fine for me and the scan does take place. Actually, mine boots twice. Once into offline mode after which there is a short delay and the scan runs then it boots again and goes back online. 

I dunno why,

Having the same problem with Windows Defender Offline (WDO) and just found this thread.  

Running Windows 10 1703, have removed all 3rd party anti-virus software, and tried all the suggestions mentioned so far in this thread.

I try to run WDO from the GUI, I get the pop up "Save your work," then I get the UAC message "Do you want to allow this app to make changes to your device", and when I click Yes, it goes back to the Windows Defender GUI without running the scan.  When I try to launch WDO from an elevated Powershell command line (i.e. Start-MpWDOScan), nothing happens..no error, nothing...just goes back to the prompt. 

Does anyone have any idea what is really causing this problem???