I have a relatively simple C# (Framework 4) console application. When I click the \"Play\" icon or hit F5 (i.e. start the program in debug mode), the icon becomes gra
See what happens if you try "Release" instead of "Debug".
If release works, then its because of a process (that you can find in Task Manager) which name is {Name of your Project}.vshost.exe
It's description is "vshost32" so you can sort by description alphabetically to find it easies.