There really isn't a happy and easy way to write about this.  The title says it all.  From the release of VS2015 and Windows 10, Windows Store Apps are no longer supported by NCrunch.

By 'support', I mean that I can't warrant that they will work with the product, I can't provide technical support for when they don't work, and will invest no further effort to maintain the integration point.

So why is support being withdrawn?  Well, there is a number of reasons:

• It's broken in a really deep way.  Windows 10 introduced some very fundamental changes to the way the application sandbox interacts with the UI.  These changes include the removal of the ability to suppress splash screens when the test environment is initialised.  The result is that if you try to run Windows Store App tests on Windows 10, you'll get a big splash screen jumping up in your face.  For a foreground testing tool like VSTest, this is annoying.  For NCrunch, it's a deal-breaker.  Because the issue is nested deep within the O/S itself, there is no way to work around it.  The MS team responsible for this area is aware of the problem, but unfortunately it doesn't seem simple to fix and it's possible we won't have a way to deal with it for quite some time.
• It's broken in at least one other way.  The installation of VS2015 (or a related update) changes the security model around the Windows Store sandbox app containers.  This has completely broken the NCrunch integration. As soon as the update is installed, NCrunch cannot initialise an app container for any version of Visual Studio installed on the system.  It's quite possible that there is a way to fix this problem or work around it, but this would still require a massive investment of time that may result in no solution at all.
• No one seems to be using it.  I know this probably isn't true, since there was a long list of people that were eager to have the Windows Store support introduced in NCrunch, but the feedback I've received is that very few people are using NCrunch to test Windows Store Apps through the sandbox.  To put this in perspective, the above problem has been present for at least 4 months now and not a single person has reported it.
• It's the boogeyman of all integration points.  There is no formal API, no documentation, no simple working example, few sensible error messages and no promise of 3rd party support for the integration of NCrunch into the Windows Store environment.  The initial integration required a herculean effort to implement and took multiple miracles to finally stablise.  For years I have lived in fear of every change MS introduced to the sandboxing, lest they change something that breaks the integration in a way that I'd be unable to fix.  And now it's finally happened.
• I have doubts about the future of this platform.  The picture is now very different from what it was back in 2013 when the integration was introduced.  Since then, Windows RT has been discontinued and Windows 8 saw enough of a backlash that Windows 9 simply didn't exist.  There is little incentive these days to write an application for the Windows Store.  Microsoft now seem to be moving in the direction of Windows Universal Apps, which are hosted in a yet another sandbox of a different kind.  I'm sure other people will have their own opinions and projections about the future of Windows Store Apps, but my role as a tools vendor is to prioritise resources to best create value for NCrunch users.  It's hard to justify investing so much more time on a platform when I'm uncertain about its future.

So if you're using the Windows Store integration with NCrunch right now, what will happen?  Well, you can continue with the toolset you're using.  The existing integration code in NCrunch won't be pulled out any time soon (perhaps never), and it will still work where it has previously.  But you should be aware that if you upgrade to VS2015 or Windows 10, it won't work and no future version of NCrunch will fix it.

I'm sorry to anyone that is relying on NCrunch for their Windows Store development.  I tried. I really did.