1 files changed, 10 insertions, 0 deletions
diff --git a/grapher/Program.cs b/grapher/Program.cs
index 85fd040..485e074 100644
--- a/grapher/Program.cs
+++ b/grapher/Program.cs
@@ -11,9 +11,19 @@ namespace grapher
         [STAThread]
         static void Main()
         {
+            var mutex = new System.Threading.Mutex(true, "RawAccelGrapher", out bool result);
+
+            if (!result)
+            {
+                MessageBox.Show("Another instance of the Raw Accel Grapher is already running.");
+                return;
+            }
+
             Application.EnableVisualStyles();
             Application.SetCompatibleTextRenderingDefault(false);
             Application.Run(new RawAcceleration());
+            
+            GC.KeepAlive(mutex);
         }
     }
 }