The error is, “The app didn’t start”. Thanks for that informative message. According to MSDN (http://msdn.microsoft.com/query/dev11.query?appId=Dev11IDEF1&l=EN-US&k=k(vs.debug.error.app_activation_failure);k(TargetFrameworkMoniker-.NETCore,Version%3Dv4.5)&rd=true), there are “no sure ways to fix these errors”. This is just another thing that doesn’t quiet work right that will hopefully be smoothed over by the first service pack.
I had this come up again, and this time I tried deleting the bin directory so that Visual Studio would have to recreate everything and I would be sure there were no hanging settings files. Sure enough, this fixed the problem and I was able to then recompile and run the app. As a side note, this seems to popup when I share my project between my Virtual Machine running Windows 8 and my physical Windows 8 box (one is on a domain, the other is an evaluation version of Windows 8).
The only other fix that I’ve found that works for this is to start a brand new Windows Store project and then add my code back in a piece at a time (and without changes to the code, it’s worked both times I’ve had to do this). This tells me that Visual Studio is probably corrupting something in the solution file since a new project works with the old code pasted in verbatim. I followed the suggested route to diagnose these errors according to Microsoft with little success as to the actual cause.
It’s not ideal, but recreate the project and that will probably fix your issue.
Also, I just found this link from someone who might have tracked down the issue in the solution. Apparently it maybe due to reference information added into the “app.config” file that has to do with version redirection.