diff --git a/OpenSim/Framework/Watchdog.cs b/OpenSim/Framework/Watchdog.cs
index c947ea6e92..3ef9ccbba0 100644
--- a/OpenSim/Framework/Watchdog.cs
+++ b/OpenSim/Framework/Watchdog.cs
@@ -178,7 +178,8 @@ namespace OpenSim.Framework
         /// <returns></returns>
         public static ThreadWatchdogInfo[] GetThreads()
         {
-            return m_threads.Values.ToArray();
+            lock (m_threads)
+                return m_threads.Values.ToArray();
         }
 
         private static void WatchdogTimerElapsed(object sender, System.Timers.ElapsedEventArgs e)