There's currently a major bug in Windows Defender, the free antivirus software that ships with Windows 10.
Running a Quick or Full scan will fail after a few seconds and only go through a handful of files, resulting in incomplete, superficial results.
Such scans are usually known to take tens of minutes, and even hours.
The issue has been widely reported over the past two days on the Microsoft tech support forums, Reddit,
and tech support sites like AskWoody, DeskModder, BornCity, and Bleeping Computer.
The bug impacts Windows Defender version 4.18.1908.7 and later, released earlier this week.
The bug was introduced while Microsoft tried to fix another bug introduced with the July 2019 Patch Tuesday.
Fortunately, there's a way around this bug, if users need to perform daily scans of sensitive systems.
Instead of relying on a Quick or Full scan, users can use the Windows Defender "Custom scan" feature and select the drives of folders they'd like scanned, manually, one by one.
https://www.zdnet.com/article/windows-defender-malware-scans-are-failing-after-a-few-seconds/
https://zdnet4.cbsistatic.com/hub/i/2019/09/18/c0659ff4-2a67-4c3a-873d-47a0ceb9e606/aea1a779ee571fd7ad079dab3bcdf9a9/windows-defender-scan.png
