After installing the latest build (9879) Windows Store Apps stopped working, I wasn't able to open even the store but after running the Windows Store Apps Troubleshooter I managed to get the Store working, furthermore, apps installed after this troubleshooting work properly but apps that were installed beforehand show up this message when trying to open them (as soon as I click on them):
Here are the results from the troubleshooter:
Original Title: in Windows 10 Build 9879 Windows Store App don't work
(Desktop applications seem to be working just fine)