PySerial could not open port COM4: [Error 5] Access is denied - please help

[John Nagle]

On 6/26/2012 9:12 PM, Adam wrote:
> Host OS:    Ubuntu 10.04 LTS
> Guest OS:    Windows XP Pro SP3
>
>
> I am able to open port COM4 with Terminal emulator.
>
> So, what can cause PySerial to generate the following error ...
>
> C:\Wattcher>python wattcher.py
> Traceback (most recent call last):
>    File "wattcher.py", line 56, in <module>
>      ser.open()
>    File "C:\Python25\Lib\site-packages\serial\serialwin32.py", line 56, in
> open
>      raise SerialException("could not open port %s: %s" % (self.portstr,
> ctypes.WinError()))
> serial.serialutil.SerialException: could not open port COM4: [Error 5]
> Access is denied.

     Are you trying to access serial ports from a virtual machine?
Which virtual machine environment?  Xen?  VMware? QEmu?  VirtualBox?
I wouldn't expect that to work in most of those.

     What is "COM4", anyway?   Few machines today actually have four
serial ports.  Is some device emulating a serial port?

				John Nagle