diff --git a/tools/GSDumpGUI/Core/Program.cs b/tools/GSDumpGUI/Core/Program.cs
index b8ec038240..11884c65e3 100644
--- a/tools/GSDumpGUI/Core/Program.cs
+++ b/tools/GSDumpGUI/Core/Program.cs
@@ -299,6 +299,15 @@ namespace GSDumpGUI
                 {
                     frmMain.lstProcesses.Items.Add(itm.IPAddress);
                 }
+                if (frmMain.lstProcesses.SelectedIndex == -1)
+                {
+                    frmMain.chkDebugMode.Checked = false;
+                    frmMain.lblGif.Enabled = frmMain.chkDebugMode.Checked;
+                    frmMain.btnRunToSelection.Enabled = frmMain.chkDebugMode.Checked;
+                    frmMain.treTreeView.Enabled = frmMain.chkDebugMode.Checked;
+                    frmMain.btnStep.Enabled = frmMain.chkDebugMode.Checked;
+                    frmMain.treTreeView.Nodes.Clear();
+                }
             }), new object[] { null});
         }
     }
diff --git a/tools/GSDumpGUI/Forms/frmMain.cs b/tools/GSDumpGUI/Forms/frmMain.cs
index 6a26822aca..66ebc8d0c3 100644
--- a/tools/GSDumpGUI/Forms/frmMain.cs
+++ b/tools/GSDumpGUI/Forms/frmMain.cs
@@ -399,10 +399,13 @@ namespace GSDumpGUI
 
         private void chkDebugMode_CheckedChanged(object sender, EventArgs e)
         {
-            TCPMessage msg = new TCPMessage();
-            msg.MessageType = MessageType.SetDebugMode;
-            msg.Parameters.Add(chkDebugMode.Checked);
-            Program.Clients.Find(a => a.IPAddress == lstProcesses.SelectedItem.ToString()).Send(msg);
+            if (lstProcesses.SelectedIndex != -1)
+            {
+                TCPMessage msg = new TCPMessage();
+                msg.MessageType = MessageType.SetDebugMode;
+                msg.Parameters.Add(chkDebugMode.Checked);
+                Program.Clients.Find(a => a.IPAddress == lstProcesses.SelectedItem.ToString()).Send(msg);
+            }
         }
 
         private void btnStep_Click(object sender, EventArgs e)