Serial communication with python

[otaolafr]

Hello,
i am running a python code to read the data from the serial print of the arduino.
i generally work in linux, and the code did work correctly without issues. but when i brought the arduino to a windows pc at work i can not make it work.
the line that fails is this one:

self.serial_port = serial.Serial(port, serialBaud, timeout=1)

port=='COM3'
i can see that the COM3 is the correct one.

1. i dont have the arduino IDE open when running the script
2. if i open i can see the serial print for com3
3. i tried going into the device adiminitrator desactivate the com3, wait, re activate it
4. i tried to change the com number of the arduino
5. i tried running inside python debugging from vscode
6. i tried running from python from powershell
7. i tried 5 and 6 as admin

non of this gave a solution.
i am always getting:

  File "C:\Program Files\WindowsApps\PythonSoftwareFoundation.Python.3.13_3.13.1520.0_x64__qbz5n2kfra8p0\Lib\tkinter\__init__.py", line 2068, in __call__
    return self.func(*args)
           ~~~~~~~~~^^^^^^^
  File "C:\Users\PC PBR\AppData\Local\Packages\PythonSoftwareFoundation.Python.3.13_qbz5n2kfra8p0\LocalCache\local-packages\Python313\site-packages\customtkinter\windows\widgets\ctk_button.py", line 554, in _clicked
    self._command()
    ~~~~~~~~~~~~~^^
  File "C:\Users\PC PBR\Desktop\franco\tempV4.py", line 265, in start
    self.serial_port = serial.Serial(port, serialBaud, timeout=1)
                       ~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Users\PC PBR\AppData\Local\Packages\PythonSoftwareFoundation.Python.3.13_qbz5n2kfra8p0\LocalCache\local-packages\Python313\site-packages\serial\serialwin32.py", line 33, in __init__
    super(Serial, self).__init__(*args, **kwargs)
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^
  File "C:\Users\PC PBR\AppData\Local\Packages\PythonSoftwareFoundation.Python.3.13_qbz5n2kfra8p0\LocalCache\local-packages\Python313\site-packages\serial\serialutil.py", line 244, in __init__
    self.open()
    ~~~~~~~~~^^
  File "C:\Users\PC PBR\AppData\Local\Packages\PythonSoftwareFoundation.Python.3.13_qbz5n2kfra8p0\LocalCache\local-packages\Python313\site-packages\serial\serialwin32.py", line 64, in open
    raise SerialException("could not open port {!r}: {!r}".format(self.portstr, ctypes.WinError()))
serial.serialutil.SerialException: could not open port 'COM3': PermissionError(13, 'Accès refusé.', None, 5)

any solution would be appreciated. i am using windows 10 and python 3.13.5

[sumguy]

It looks like you are using the serial port in a class, can you show how the port name and the baud rate are assigned and the part that initializes and opens the serial port.

[van_der_decken]

"Access denied" sounds like something else has that com port open.