Removing unused COM numbers

Every time a USB device that represents a COM port (such as the BSF-7-USB) is plugged into a different USB port of a computer, a new COM number will be assigned.  If you change USB hubs there’s a whole new set of USB ports!.

Eventually there are no numbers left below 16, but SI-Config needs the COM number to be below 16.

The following trick allows you to clean up the unused COM ports:

First start a Command Prompt session in Administrator mode (right-click on the Command Prompt link in Start Menu | All Programs | Accessories, and select Run As Administrator).

type in the following commands:

set devmgr_show_nonpresent_devices=1

start devmgmt.msc

Once the device manager starts up, there’s an extra menu item in the View submenu.

Select it so that the checkmark is there.


Now expand the Ports (COM & LPT) section to see all COM ports.

Now you can select an extra COM port, and uninstall it.


I do not delete the drivers for the device:


Insure you don’t delete anything important!  You’re in charge, I’m not. 

After I deleted all the SPORTident USB to UART Bridges, I inserted my BSF-7-USB, and the computer now had to re-install the driver (but I didn’t have to download it again).  Once the installation was done (took about a minute), I now have it installed on COM4.  All is good!

[Thanks to for coming up with this trick]

Print | posted on Saturday, August 30, 2014 10:30 PM

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