Yesterday evening, several users reported a failure of Windows Defender. Windows Defender could not be restarted or kept trying to crash with the message that the threat service was being stopped. Restarting the system only worked for a short time.
The Original Cause Of The Problem Was Most Likely An Incorrect Signature Update
However, it is unclear which signature file is responsible. An administrator reported that after installing the update, which distributed the signature file version 1.313 crashed almost 500 clients when scanning through protection. On the other hand, the first user reports on this problem date a few days back.
Users who found out that the threat service of the Microsoft virus protection solution crashed as soon as a file was scanned, occurred with two points in the file name for the file name extension. Such a dangerous bug, which theoretically could also have been used by attackers to pry out virus protection in order to execute malicious code, could also explain why some users experienced no or rare crashes.
Systems that have obtained this update and updated the scan engine should no longer be affected by the error. If the error cannot be remedied automatically via an update, users can intervene it manually. To update, the author’s Windows 7 system had to be checked manually for updates and the security intelligence update for Microsoft essentials.
In Windows 10, the Windows Security window should be opened instead. There, select the threat protection category and select check for updates. If the said hyperlink is not displayed in the Windows 10 security center or if the process cannot be carried out for other reasons, the editorial team observes that the manual triggering of the general update search can also help instead.