If you do a fair amount of developing with serial devices then you eventually reach a point where your computer has 20 or 30 comm ports listed as “in use.” This can become a rather large annoyance when working with programs that only allow you to use the first 10 ports. Sure, you can manually set a device to use a port that’s listed as “in use” but this could potentially cause issues.

There’s a trick that will let you see the hidden devices that are eating up your COM ports:

Enter set devmgr_show_nonpresent_devices=1 into Command Prompt Open Device Manager Click View -> Show Hidden Devices

Now when you expand the section on COM ports, the non present COM ports will be in grey. You can now easily remove any unwanted devices that are tying up COM ports by Right Clicking then selecting Uninstall. After you are done, should you wish to hide these devices again you can do so by entering

set devmgr_show_nonpresent_devices=0 in Command Prompt.