How can I solve my port detection problems?

Each time I try to discover XBee modules with my USB explorer, it says it can perform the operation because the port com is already used.
When I unplug, then replug the USB explorer, it works, but only for one time.
I need to perform this operation each time I want to perform something on my XBee…
What is happening.

For the record, 12 hours ago, everything was working fine. The problem appeared suddenly.

I tried to uninstall all COM ports, install the last FTDI driver, with no success…

Any idea?

Sounds like the USB driver is not properly installed or you have a software application that is not releasing the port.