I ran into the same problem.
I installed the Windows 10 upgrade over Windows 8.1 which was running Start8.
Once in Windows 10, I tried uninstalling Start8... it was painful and overall not clean.
I then installed Start10. It will not work with the "Windows 10 Menu" or anything in the icon driven desktop, such as Store or the like. What happens is that I get a thin frame show up on the desktop and then it disappears. In the Task Manager there is no indication the app is running.
As long as I stay in the desktop mode with the related programs, all seems to be okay.
Not sure how to fix this at this point.
Anybody have any ideas?
Oh, If I uninstall the Start8 or Start10 program in Windows 10, the remaining icon does not display any menu when clicked on. If right-clicked, then it brings up a menu with many of the needed links.
Wonder if anyone has experienced the same and if there are any fixes.