Which version of 8.1 is it? I found that 8.1 2016-08-02 would not run on latest Windows 10, however I took the executable from 8.1 2016-08-30, pasted it into the client folder, and then it worked.
I would like to know what BackgroundHALShouldPause does, and how to use it. While it's listed in the HAL Primitives report, it is not used in source code and it doesn't appear in the LMS HAL...