It's not clear what you are doing.  Can you show us a complete, simple test
case? I don't want your entire app, just a small test case that shows the
behavior you don't like or do not understand.

For example, below is a test that illustrates a mutex.  Compile the code,
then open 2 command windows and run the exe in both.  You will see the
instances of the app obtaining and releasing the mutex.   Does this do what
you want?  If not, why not?

-Dino

// ---------------------------------------------------------------------
namespace Ionic.Demo {

 public class MutexTest1 {
   static string MutexName= "MutexTest";
   static int SleepTime= 4000;
   System.Threading.Mutex  MyMutex= null;

   public void TryAgain() {
     bool stat= false;
     int i;
     for (i=0; i < 11 & !stat; i++) {
       stat= MyMutex.WaitOne(SleepTime/10+100,true);
     }
     if (stat) {
       System.Console.WriteLine("Obtained the mutex on cycle {0}", i);
       System.Console.WriteLine("Sleeping for {0}", SleepTime);
       System.Threading.Thread.Sleep(SleepTime);  // in ms
       MyMutex.ReleaseMutex();
     }
   }

   public void InitialTry() {
     //create a mutex with a unique name
     MyMutex= new System.Threading.Mutex(false,MutexName);

     // initial attempt to grab:
     if (MyMutex.WaitOne(10,true)) {
       System.Console.WriteLine("Got the mutex. Sleeping for {0}",
SleepTime);
       System.Threading.Thread.Sleep(SleepTime);  // in ms
       // release
       System.Console.WriteLine("Releasing the mutex....");
       MyMutex.ReleaseMutex();
       System.Threading.Thread.Sleep(120);  // in ms
       System.Console.WriteLine("Trying to re-acquire the mutex....");
       TryAgain();
     }
     else {
       System.Console.WriteLine("Could not get the mutex at startup.
Polling...");
       TryAgain();
     }
   }

   public static void Main(string[] args) {

     MutexTest1 me= new MutexTest1();
     me.InitialTry();
     System.Console.WriteLine("exiting...");
   }
 }

}