I checked the Windows event viewer and found that an error thrown by the Win_KB_Service_cmd.bat script held the key:
Could not find jvm.dll
Could not find jvm.dll in C:\Program
Files\Java\jre1.8.0_181\bin\hotspot\jvm.dll or C:\Program
I checked my C:\Program
Files\Java\jre1.8.0_181\bin folder and found a “server” folder containing the “jvm.dll” but no client folder there.