Recent tests showed that Windows Defender, Windows 10, offers the same performance as various trusted third-party software.
However, a bug recently found in Windows Defender destroys this near-perfect antivirus experience. Windows 10, as it causes problems during scans.
The bug mentioned by BornCity, and appeared after the March 2020 updates, when Microsoft released security updates for Windows and other products.
Following these updates, there are users who claim that Windows Defender overrides certain files during a quick or complete scan, as if there were exceptions on their devices. Note that these users did not add file exceptions but Windows Defender simply bypasses file scans without being asked.
Users experiencing this behavior also receive an error message in Action Center stating:
"Items were not scanned during the scan. Scanning Windows Defender Antivirus overrides an item because of network exclusion or scan settings. ”
At first glance, this problem seems to exist in the version of AntiMalware after the updates released by Microsoft. However, it appears that there are files that are skipped during the scans, regardless of the version of the Antimalware Client, which may mean that the error does not necessarily exist in Windows Defender.
You may be able to see this behavior on a Windows 10 1909 device. Update virus definitions to the latest version of the Antimalware Client. You will see that although there are no exceptions on your computer the message will appear in the Action Center after a quick scan.
Microsoft has not identified the problem, so it is not yet clear if this is an individual problem or if it affects a significant number of devices.
The next Patch Tuesday will take place on April 14, to see if we have any news by then.