Occasionally Windows can get confused and orphan both physical and virtual comports. These ports are not visible to the user in Device Manager, but Windows will enumerate them causing failures when trying to create a virtual com port where one invisibly already exists.
This procedure will in most cases allow the user to un-hide hidden com ports in order to delete them eliminating possible com port conflicts.
Before starting, shut down your radio and close any programs what may be using the virtual com ports, like SmartSDR CAT or other third-part applications.
1.) Click Start, point to All Programs, point to Accessories, and then click Command Prompt.
2.) At a command prompt, type the following command , and then press ENTER:
set devmgr_show_nonpresent_devices=1
3.) Type the following command a command prompt, and then press ENTER:
start devmgmt.msc
Troubleshoot the devices and drivers in Device Manager.
4.) Click Show hidden devices on the View menu in Device Manager before you can see all devices associated with the computer.
5.) Scroll down to the Ports section and you will be able to see all the hidden and unused COM ports. The hidden com ports have a grayed out icon next to them.
6.) To delete a particular port, click to highlight it and hit the Delete key on your keyboard. In the Confirm Device Removal dialog box, click OK.
7.) After you have deleted the unused and hidden COM ports, the list will show only those COM ports you use or may use in the future. Be careful not to delete com ports that are working properly.
8.) When you finish troubleshooting, close Device Manager.
9.)Type exit at the command prompt.
Note that when you close the command prompt window, Window clears the devmgr_show_nonpresent_devices=1 variable that you set in step 2 and prevents ghosted devices from being displayed when you click Show hidden devices.