How to enable/disable compile errors warning in Visual Studio

1. From the "Tools" menu, select "Options".
2. In the dialog that appears, expand "Projects and Solutions", and click "Build and Run".
3. On the right side, you'll see a combo box labeled "On Run, when build or deployment errors occur".
   
   • If you want to disable the message box, select either "Do not launch" or "Launch old version" (which will launch the old version automatically).
   • If you want to enable the message box, select "Prompt to launch" which will ask you each time.

   
Of course, as people have suggested in the comments, this means that your code has errors in it somewhere that are preventing it from compiling. You need to use the "Error List" to figure out what those errors are, and then fix them.