“Invalid Procedure Call” After Installing Windows Update

The August 13, 2019 Windows Update KB451250 for Windows 7, 8.1 and 10 can cause many applications including At Your Service to stop responding or present an error “Invalid Procedure Call” when run. Microsoft is aware of this issue and has provided additional patches to fix the issue.

Below are links to the various patches, depending on your operating system. Please install these patches if you are experiencing this issue after installing the August 13, 2019 update.

Windows 10, Windows Server 2016 and Windows Server 2019


Windows 8.1 and Windows Server 2012 R2


Windows 7 SP1 and Windows Server 2008 R2 SP1