Modem in Use by another process


A modem can only be used by one program or process at any given time.  You may encounter the message "com port is in use by another process".  The means and can only mean one thing...


Snappy fax tried to access the modem's com port and Windows denied the process with a message that another process is using the com port.  The usual culprit is either the Microsoft Fax service (or Windows fax and scan, if using Windows Vista or Windows 7) or perhaps the Winfax service if you have been a Winfax user.  If neither of these apply then you will need to find the culprit and shut it down as Windows provides not way to discover what other process is using the port, not any way to wrest control of the port from that process.  You can be absolutely certain that some process *is* using the com port when you see this message.  See the topic 'Special Topics | Disabling the Microsoft Fax Service' in this help file.  If the Winfax service is the problem then the process is similar but with respect to the Winfax service instead.


If you are using Windows Server then it is likely that Windows itself is looking for incoming network connections on the modem's com port so configure the incoming connections to not use the modem's com port.