Slow debugging issue in Visual Studio

I have seen this before. Try deleting all your breakpoints and then set the ones you want. Hit F5. Is it faster now?

I just noticed that you mentioned setting up the .NET source debugging feature. Try to disable that. Your network connectivity to Microsoft's source server may be slow. Also disable any symbol server connectivity in menu Tools → Options → Debugging → Symbols.

Also try disabling "Enable property evaluation and other implicit function calls" in menu Tools → Options → Debugging → General.

Or remove your .suo file which can be found next to your solution (.sln) file. This solved an issue I had with debug sessions taking a long time to start and stop.

You may need to delete all your breakpoints---note that you need to click the "Delete all breakpoints" button (or use Ctrl + Shift + F9), NOT just delete them one by one. If Visual Studio has mangled your solution settings the latter will not work. You may need to add a breakpoint first, in order for this to work (clever, eh?).

If worst comes to worst, you may need to delete your .suo file and let Visual Studio start a new one from scratch. Note that you will lose your personal solution configuration settings, however (only for this solution, not any others). However, you may want to move/rename the file temporarily until you determine whether or not this is the problem; that way, you can always move it back. I have seen some online resources recommend deleting (moving/renaming) the .ncb file as well.