The issue is a result of a Microsoft Windows Security Update, which affected all antivirus scanners (i.e. Sophos, AVG, Avast, Thirtyseven4 and others).
This is not a result of a Thirtyseven4 false positive or similar. This was a faulty Microsoft Security update release.
However, we do apologize for any inconveniences that you are experiencing, and we are working with and awaiting updates from Microsoft.
The temporary solution is:
If you have performed the update but have yet to reboot, we recommend removing the update prior to rebooting.
KB4493467 & KB4493446 - Windows 8.1, Windows Server 2012 R2
KB4493450 & KB4493451 - Windows Server 2012, Windows Embedded 8 Standard
KB4493448 & KB4493472 - Windows 7 Service Pack 1, Windows Server 2008 R2 Service Pack 1
Windows 10 1709: KB4493441
Windows 10 1803: KB4493464
Windows 10 1809: KB4493509
Windows 10 1903: KB4495666
Example:
Steps to remove KB4493509
1) Boot/start system in Safe Mode with Networking
2) Open Start > Search for Command Prompt, right-click the top result, and select Run as administrator.
3) Type the following command to remove the update and press Enter:
wusa /uninstall /kb:4493509