That's not the same thing exactly. When you start VS, are you right-clicking the exe or shortcut and choosing Run As Administrator? If you have UAC turned on you will need to do this even if you are a local admin or VS will not be able to register your components properly. You can tell that VS has been started as admin if Microsoft Visual Studio (Administrator) appears in the title bar. If UAC is turned off, then this is not necessary. As far as I know, ArcMap loads whatever extensions are registered no matter what account is used to kick it off. If your extension isn't present, then that usually means it isn't registered. If you simply compile without starting the debugger does your extension show up under ESRI Mx Extensions in Categories.exe? If so, remove it and compile again to see if it comes back.