I have an asp.net application which uses process.start to call an executable (Graphviz). All works well in my development environment, but when I move to production I\'m no
Locate your pool under which your site is run, and see under which user is running.
If you can't do that you can run this code to see the user that your pool is running:
var user = System.Security.Principal.WindowsIdentity.GetCurrent().User;
var userName = user.Translate(typeof(System.Security.Principal.NTAccount));
And then give permission to that user to be able to run these files.
reference: How to find out which account my ASP.NET code is running under?