I use Bluetooth serial ports daily. Over the years I've noticed that the number of the virtual COM port created when I connect is getting higher and higher. Certain ports are now locked out, seemingly forever. This is a problem because a "feature" of my client program is that it can't access COM ports numbered higher than 16.
I'm now in a situation where I can only connect Bluetooth serial ports to COM10 and COM11. COM1 is the regular port, COM3 is a modem.. but the others are a mystery. COM12-14 and 20-22 are taken by system services. It's very useful to be able to connect to more than two devices at once, so only having two ports available is problematic.
Literally every time I reboot my computer (a Dell laptop), I have to go into Device Manager and uninstall all the Bluetooth COM ports, then go into BlueSoleil and recreate the Bluetooth serial ports before I can connect anything to COM10 or COM11.
I used to be able to use COM2 and COM4-9. Those ports don't appear in Device Manager as being used, but I cannot access them.
I've gone through several different Bluetooth dongles, so it's not unlikely that there's a mess going on with the drivers.