Windows 10: Defender Quick Scan only takes 20 seconds to complete -- Is it really scanning?

I took a backup of a Windows 2012 R2 system. I restored that backup to a directory on a Linux server and exported that backup as a samba share. I mounted the samba share on a Windows 2019 system and ran the following defender command line from a cygwin shell. The command line completes in 20 seconds, but doesn't report "found no threats"$ time ./MpCmdRun.exe -Scan -ScanType 1 -DisableRemediation -File "W:\C"Scan starting...Scan finished.real 0m21.175suser 0m0.000ssys 0m

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Windows Defender - Quick Scan

Windows defender no longer offers a quick scan option.

My options are:

• Scan
• Advanced Scan

• Full Scan
• Custom Scan
• Windows Defender Offline scan

Whichever option I check, the scan will need to run for hours to complete.

Is a quick scan available?

How do I restore this feature?

 

Windows Defender quick scan fails to complete

When I try to employ a "Quick Scan" procedure in Defender, the scan progress indicator, coloured green, stops half way and does not complete.

The files scanned number continues the count as if it is doing a full scan.

My Windows 10 updates are correct as our the virus definitions etc.

Any suggestions on why the "quick" scan fails to complete?

Thanks

[Original title: Windows 10 Defender]

 

Does Windows Defender Quick scan interrupt Advanced scan?

Before I create a System Image, I run an Advanced scan using Windows Defender, and it typically takes about an hour and the Scan history lists about 4,000,000 files scanned. However, often I see only about 40,000 files scanned, what I get from a Quick scan.

I can think of two explanations that might account for this:

1. The Advanced scan completes, but a Quick scan starts afterwards and wipes out evidence that that the Advanced scan occurred (unless presumably some problem was found).

2. The Advanced scan is interrupted and a Quick scan runs.

Are there other possibilities?

The 2 possibilities listed above are both unsatisfactory because I can tell if an Advanced scan was completed. If an Advanced scan was just completed, there is no reason that a Quick scan should be run automatically.