diff --git a/platformio/debug/command.py b/platformio/debug/command.py
index 278ca463..a2484769 100644
--- a/platformio/debug/command.py
+++ b/platformio/debug/command.py
@@ -172,11 +172,12 @@ def debug_cmd(
             signal.signal(signal.SIGINT, signal.SIG_IGN)
             loop.run_until_complete(coro)
             if IS_WINDOWS:
+                client.close()
                 # an issue with `asyncio` executor and STIDIN,
                 # it cannot be closed gracefully
                 proc.force_exit()
         finally:
-            del client
+            client.close()
             loop.close()
 
     return True
diff --git a/platformio/debug/process/client.py b/platformio/debug/process/client.py
index 6a6f1b9e..3a017e7b 100644
--- a/platformio/debug/process/client.py
+++ b/platformio/debug/process/client.py
@@ -66,6 +66,14 @@ class DebugClientProcess(DebugBaseProcess):
             self._server_process.terminate()
         super(DebugClientProcess, self).process_exited()
 
+    def close(self):
+        self._unlock_session()
+        if self.working_dir and os.path.isdir(self.working_dir):
+            fs.rmtree(self.working_dir)
+
+    def __del__(self):
+        self.close()
+
     def _kill_previous_session(self):
         assert self._session_id
         pid = None
@@ -94,8 +102,3 @@ class DebugClientProcess(DebugBaseProcess):
             return
         with ContentCache() as cc:
             cc.delete(self._session_id)
-
-    def __del__(self):
-        self._unlock_session()
-        if self.working_dir and os.path.isdir(self.working_dir):
-            fs.rmtree(self.working_dir)