Comments on: How to Remove COM Ports Which Are In Use

By: MikeE

MikeE — Wed, 16 Nov 2011 22:52:34 +0000

One thing that “I” found to work. The above did not work for me as the ports were “(In Use)” but no device was listed. I had the lower 4 com ports “(In Use)” when i knew that the system only had one physical port. I used the advance button to assign the one actual port (COM1) to the other 3 “(In Use)” ports and then back to COM1. This effectively cleared the “(In Use)” status and the virtual drivers were then able to assign to 2,3,4,etc.,

Hope this might help someone else if the above doesnt fix their problem.

By: scott

scott — Sun, 30 Oct 2011 20:24:15 +0000

thanks Lars, works great!

By: Lars

Lars — Fri, 23 Sep 2011 08:23:16 +0000

I got this to work on Windows 7 64bit! The trick was to open the Command Prompt as administrator and start the Device Manager from the same command prompt.

1. Right-click “Command Prompt” in Accessories and choose “Run as Administrator”

2. Enter “set devmgr_show_nonpresent_devices=1″ – without the quotes obviously

3. Enter “start devmgmt.msc”

4. In the box that opens, select “Show hidden devices” in the ‘view’ menu.

Now if you expand the section on COM ports, all the COM ports that have ever
been created will be displayed, the non present ones being in grey. You can
uninstall away anything that you don’t want (right click, select uninstall).

By: David

David — Tue, 30 Aug 2011 12:32:56 +0000

I have a situation that I have installed 3 usb to serial hubs to connect 10 POS for text overlay. I am only able to setup 2 ports. All the others it states are in use – currently it shows 14 com ports only com11 and 14 I can use. but the rest it states are in use. How do I release the com ports with in windows 7 and how do I see what devices are using them

By: Patrick O'Keeffe

Patrick O'Keeffe — Tue, 24 May 2011 23:33:43 +0000

This won’t work (at least on Windows XP SP3) until the computer is restarted. Minor but important and very inconvenient step. Thanks MS for the hassle.

By: Kurt

Kurt — Fri, 04 Mar 2011 15:20:55 +0000

I can confirm that this didn’t work on Win 7 64. However, I have a tripplite serial adapter and it lets you change the com port to one that windows thinks is already in use. I changed it from Com 11 to com 3 and it’s working good. No hack necessary.

By: FettesPS

FettesPS — Sat, 19 Feb 2011 16:59:51 +0000

@Jay Sheldon – Can’t say that I’ve tried this in Windows 7 or Windows Vista.

By: Jay Sheldon

Jay Sheldon — Thu, 17 Feb 2011 00:15:01 +0000

I have tried this in Win 7 x64 and I do not see the ports that are not connected. I am using a USB to Serial adapter (FTDI – virtual com) and when the usb side of the device is connected to the computer it shows in Device Manager, when the usb side of the device is not connected to the computer is does not show in Device Manager (even when using your directions)

Please advise!