diff --git a/Whisper.net/WhisperProcessor.cs b/Whisper.net/WhisperProcessor.cs
index a56aca2a5..e9fc49bc5 100755
--- a/Whisper.net/WhisperProcessor.cs
+++ b/Whisper.net/WhisperProcessor.cs
@@ -229,7 +229,10 @@ bool OnWhisperAbortHandler()
 
         try
         {
-            options.OnSegmentEventHandlers.Add(OnSegmentHandler);
+            lock (options.OnSegmentEventHandlers)
+            {
+                options.OnSegmentEventHandlers.Add(OnSegmentHandler);
+            }
             options.WhisperAbortEventHandler = OnWhisperAbortHandler;
 
             currentCancellationToken = cancellationToken;
@@ -261,7 +264,10 @@ await Task.WhenAny(whisperTask, resetEvent.WaitAsync())
         }
         finally
         {
-            options.OnSegmentEventHandlers.Remove(OnSegmentHandler);
+            lock (options.OnSegmentEventHandlers)
+            {
+                options.OnSegmentEventHandlers.Remove(OnSegmentHandler);
+            }
         }
     }
 
@@ -776,7 +782,9 @@ private void OnNewSegment(IntPtr state)
                     language!,
                     tokens);
 
-                foreach (var handler in options.OnSegmentEventHandlers)
+                OnSegmentEventHandler[] handlers;
+                lock (options.OnSegmentEventHandlers) { handlers = options.OnSegmentEventHandlers.ToArray(); }
+                foreach (var handler in handlers)
                 {
                     handler?.Invoke(eventHandlerArgs);
                     if (currentCancellationToken.HasValue && currentCancellationToken.Value.IsCancellationRequested)