This guide was first published on Mar 07, 2013. It was last
updated on Mar 07, 2013.
This page (Overview) was last updated on Jun 16, 2019.
This mini tutorial will show you how you can find and uninstall all those extra COM ports you may have registered from years of microcontroller-hacking.
You may have noticed that every time a new FTDI-based board is plugged in, you get a new COM port. You might also get new COM port assignment with adapters, etc. Eventually you can get into pretty high COM port numbers and that can be really annoying! For example, on my 6-month old Windows 7 install I'm already up to COM38!
At some point you may want to figure out what were all those other COM ports and perhaps uninstall the "ghost" devices. Under windows this isn't particularly easy unless you know how. Luckily, this tutorial will show you how and its really easy once you know!
First up, you'll have to open up a Command Prompt and in Windows 7 it has to be run as administrator. Open up the start menu and start typing in "Command" until the black C:\ icon appears. Right click and select Run as Administrator If you have some other version of Windows, you may not have to run as admin.
Now type in set devmgr_show_nonpresent_devices=1 (which is the magic command to show ghost devices) followed by start devmgmt.msc (which starts up the device manager)
Now you're almost done, select Show hidden devices from the View menu
Voila! You can now see every COM port you've ever made, and you can also now select which ones you want to uninstall so the COM port number can be recycled