Windows 10 - Defender Offline Scan not working

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,

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

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?

We appreciate the provided information. To further isolate your concern, we'd like to ask if you have other antivirus program installed on your device? If yes, we highly suggest that you uninstall it to prevent software conflicts. In addition, you can also follow the steps provided on this article on how to troubleshoot Windows Defender. Once you're done, replicate the concern and check if you encounter the same error.

We'll appreciate if you can send us an update.

Windows 10 Version 1703

No errors, Offline Scan asks me for confirmation to make changes to my hard drive, I click yes, window closes. Windows Defender updates the last scan time but nothing actually happens, or at least there is no indication that anything happened. Says it should restart device when it is finished but that has never happened yet either.