MATLAB Answers


Error refreshing com ports

Asked by Stiphu
on 5 Mar 2013
Latest activity Commented on by Siddharth Rajesh on 19 Jul 2016

My computer is connected to a LED light source over a virtual com port. The LED light source crashes from time to time. If this is the case, I have to restart it, which I can do over this com port (the crash is a power failure. The light source is not working properly anymore, but I still can communicate with it). The problem is, that after the restart, I'm not anymore able to connect to it. I'm trying to establish a new connection with

    connection = serial('COM14','BaudRate',9600);

If I execute the fopen command, I get the following error message:

    Error using serial/fopen (line 72)
    Open failed: Port: COM14 is not available. Available ports: COM12,
    COM14, COM15.
    Use INSTRFIND to determine if other instrument objects are connected to    
    the requested device.

If I restart Matlab, I am able to reconnect. Do you know if there is any workaround?


I'm experiencing the same problem and would be very interested in a solution (port unavailable, yet available). The port is closed and deleted, yet I get the following message:

Open failed: Port: COM3 is not available. Available ports:

It can be solved by restarting the system. Until it fails again after some hours of com port use.

I had the same problem. There is a similar post ( ) in which a working solution is presented.

Essentially you can resolve the problem by issuing the following command


This statement has solved my issue, thank you so much for you help.

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