I had a nasty problem today with Windows 8 dev license and packaging an app for Windows Store. Basically after i have created a package for Windows Store, my Windows dev license expired. I dutifully updated the license and then lo and behold....everytime i wanted to run/debug the solution from Visual Studio i got this :
"Unable to activate Windows Store app. The activation request failed with error 'The application cannot be started. Try reinstalling the application to fix the problem."
Looking at the Event Log i found out that the app cannot be started because it's in state "17". Brilliant.
Googled for this problem and found some stuff here150151. Unfotunately none of those stuff worked for me.
The working fix for me was to create a new Windows Store project , move the files from older one (without Package.appxmanifest, Package.StoreAssociation.xml, *.pfx ) and voila....it runs fine now.