I have a simple video encoding worker role that pulls messages from a queue encodes a video then uploads the video to storage. Everything seems to be working but occasionally when deleting the message after I am done encoding and uploading I get a "StorageClientException: The specified message does not exist." Although the video is processed, I believe the message is reappearing in the queue because it's not being deleted correctly.

• Is it possible that another instance of the Worker role is processing and deleting the message?
• Doesn't the GetMessage() prevent other worker roles from picking up the same message?
• Am I doing something wrong in the setup of my queue?
• What could be causing this message to not be found on delete?

some code...

  //onStart() queue setup
  var queueStorage = _storageAccount.CreateCloudQueueClient();
  _queue = queueStorage.GetQueueReference(QueueReference);
  queueStorage.RetryPolicy = RetryPolicies.Retry(5, new TimeSpan(0, 5, 0));
  _queue.CreateIfNotExist();


 public override void Run()
  {
        while (true)
        {
            try
            {
                var msg = _queue.GetMessage(new TimeSpan(0, 5, 0));
                if (msg != null)
                {
                   EncodeIt(msg);
                   PostIt(msg);
                   _queue.DeleteMessage(msg);
                }
                else
                {
                    Thread.Sleep(WaitTime);
                }
            }
            catch (StorageClientException exception)
            {
                BlobTrace.Write(exception.ToString());
                Thread.Sleep(WaitTime);
            }
        }
    }