First of all I would like to say that I already tried all the solutions I could find on the internet, including Unable to Activate Windows Store App
I recently upgra
Ensure that ALL APPLICATION PACKAGES has "read" permissions on C:\Windows.
My organization's group policy likes to strip all permissions from C:\Windows, including the ALL APPLICATION PACKAGES group . By adding it back in and setting Read & execute, List folder contents, and Read, I'm able to run the app from Visual Studio without any problems.
See What to do if your Windows 8 Modern App fails to start for more tips, including this one.