diff --git a/pyocd/probe/pydapaccess/interface/pyusb_v2_backend.py b/pyocd/probe/pydapaccess/interface/pyusb_v2_backend.py
index 145497f28..eadf465d5 100644
--- a/pyocd/probe/pydapaccess/interface/pyusb_v2_backend.py
+++ b/pyocd/probe/pydapaccess/interface/pyusb_v2_backend.py
@@ -150,6 +150,7 @@ def start_rx(self):
 
     def start_swo(self):
         thread_name = "SWO receive (%s)" % self.serial_number
+        self._swo_thread_did_exit = False
         self.swo_thread = threading.Thread(target=self.swo_rx_task, name=thread_name)
         self.swo_thread.daemon = True
         self.swo_thread.start()