Why am I unable to restart the Cerberus FTP service without rebooting the server?

Symptom

After installing Windows Update KB4338818 on their Windows machine, administrators may notice that they are unable to successfully stop or restart the Cerberus FTP Service via the Windows Services Manager as it will never complete. Furthermore, it is only possible to restart the Cerberus FTP Service by restarting the Windows server itself and there are no corresponding errors that can be found in either the Cerberus logs or Windows event logs. 

Root Cause

Windows Update KB4338818 introduced a bug where some services will remain in a "stopping" state but is unable to fully stop or be restarted (please refer to the known issues list for more details). In other words, Cerberus will attempt to make an OS system call that closes sockets when attempting to stop or restart the service, but this OS system call hangs and never returns when the application makes this call. 

Note: This issue will actually affect any application that utilizes this OS system call, and has been widely reported by many other applications or Windows users. 

Also, this known Windows Update issue will affect the following operating systems (but is not necessarily limited to just the operating systems listed below):

• Windows Server 2008 and Windows Server 2008 R2
• Windows Server 2012 and Windows Server 2012 R2
• Windows Server 2016
• Windows 7/8/10

Resolution

Either roll back Windows Update KB4338818 or install Windows Update KB4338821, which is currently only a recommended update, on your machine/server.