1 ~ 2 months ago after patched Windows 7 Pro. 32 bits, the VMware guest cannot access to the host serial port. Need to manually disable the serial port (in host) and enable it back; than the guest can connect to it (serial port which connected to a dot matrix printer). Once reboot / shutdown the host the problem comes back. It looks like the serial port is occupied by some program when the Windows started. How to find out which program is using the serial port. Can anyone help? Thank you in advance.