Windows 10: How can I tell if a Windows Defender offline scan ran successfully?

I am running MS Win 11 Pro Version 24H2 OS Build 26.100.2894This should be up to date.I set up a Microsoft Defender Offline Scan. It logged me out, rebooted, showed a progress screen of the percentage of files that had been scanned and then.....went to the login screen.Did the offline scan work? Was it successful? Did it find any problems? I have no idea. I've done multiple searches to try to determine whether the scan found anything amiss and have come up empty. The offline scan doesn't seem to leave any trace.For Scan options I see "Last Scan: Not Available"For Protection History it says "

:)

 

How to tell if Offline defender scan ran successfully?

How do I tell which of those events are normal defender antimalware running vs. the offline scan?

I did a "find" on MALWAREPROTECTION_OFFLINE_SCAN_INSTALLED

But it didn't find that anywhere. Does that mean it didn't run for some reason, or does find not work for that?

 

How to tell if Offline defender scan ran successfully?

Well, I downloaded and ran the MSSSTool64.exe to create a bootable USB with the offline scanner on it. When I booted, it complained about not having some sort of signature.

Then I went into the BIOS and disabled the "Secure boot" option. Now I could boot from the USB. AND a version of Windows loaded and started the offline scanner program. That was a little progress. However, then when it tried to perform the scan, it couldn't
find a Windows drive to scan.

I'm guessing that the Windows drive is only accessible when the machine is booted in Secure boot mode. And the Offline scanner ISN'T set up to run in secure mode either on the USB drive or when booted to from the Defender UI.

So now what? Is there a way to make the USB be "Secure boot"able so that it could boot AND scan the harddisk?

Or did Microsoft just not figure out how to update this part of Defender for use with Secure boot?

I hate it when one problem leads to another which leads to another and so forth down the rabbit hole.

 

How to tell if Offline defender scan ran successfully?

You didn't answer my question about the file location. Do you know if there should be such a folder? It doesn't exist.

Also, I think for a while, if I click on the protection history, the Defender dialog crashes. It works fine on my wife's machine.

… time passes ...

Ok, I was able to find the History.log file in "C:\ProgramData\Microsoft\Windows Defender\Scans\History\Service". However, it is empty even though quick scans and full scans have been run in the past.

My wife's machine runs the offline scan fine and the file contains information.