what is the version of Java ? Are you able to launch it from any other Server ?

Which browser do you use?  On Win8, you have IE 64bit and IE 32bit and it might be you need both javas.  Try combination and see if it works.

I've tried IE, FF, Chrome, Opera, Vivaldi

Why does the browser matter? Once I download the jnlp file I should be able to open it with javaws. That is how I'm using it on the Win10 host.

currently I have jre1.8.0_92 working on a Win10 system but a Win8 will not. I've verified all Java settings are identical on each system and checked the java.security file

It 32bit vs 64 bit that matters.  As I said, by default you might have one type of java and need second one (which then depends on browser).  That's one of possibilities.

You might need You could try this.

Run -> javaws -viewer.

Select all the apps in "Java Cache Viewer" and select delete.

On the "Java Control Panel", go to the tab "Security" -> Select "Medium" -> "Edit Site list" and add the URL for the NMC in here,

Before Clicking on OK, click on "Restore Security prompts"  -> "Restore All".

Wow typing so many quotes is difficult.

I already have tried all of those things. It seems like I need to do some certificate updating on the server side wrt EMC but I'm coming up empty. Also like the old key length fix from 2048 to 1024 in java.security

the working Win10 only has 64b java bits

installed 32bit alongside 64b. still same error

any other ideas.

getting JAR resources in JNLP file are not signed by same certificate