Hi Ryan Archibald,
The 'Untested Windows Version' warning has not been observed to cause issues in computed results so this can be ignored.
The diff files are created using a Java utility. The absence of their content indicates Java may not be configured on your new Windows 2016 OS.
Please open CMD console and execute the following to determine if Java is available
If no Java is available you will need to install it.
Unfortunately, there is not a way to regenerate the diff files without rerunning all the sample cases.
Best regards,
Rob Lefebvre
SCALE Code System