diff --git a/main.py b/main.py
index 210569b..d8d4f74 100644
--- a/main.py
+++ b/main.py
@@ -444,6 +444,7 @@ class ArduinoGUI:
             if self.ser:                
                 if self.ser.in_waiting:
                     try:
+                        command = ""
                         command = self.ser.read_all().decode(errors='ignore').strip()
                         while self.ser.in_waiting:
                             pass