1) Please bear in mind that the default options with the debugger are to throttle debug messages if breakpoints are hit within 50 milliseconds of each other. This means your arduino might run slower than normal.
 
2) The debugger should only be tested with arduino projects that will not cause damage, loss of human life or any other dangerous outcome. 

As usual with Visual Micro, I/we take no responsibility for any loss or damage caused directly or indrectly by any feature(s) of the visual micro program.

3) The debug tools upgrade (msi) is NOT a full install of Visual Micro, the msi installs debug support files only.

To use the debugging and/or to use Visual Studio 2012 you need to have the latest version of Visual Micro installed from codeplex (click downloads at the top of the main visual micro web site)