I have too many BEs, and I have quite a lot of hubs, and I like shuffling them around, trying out different topologies, and I am not always consistent which ports which hubs and BEs are plugged into.
Is that a problem? On Windows: yes. Windows will create a new device entry for each connected device in each new permutation. If you use bfgminer with COM port emulation, a new bridge port will be created for each BE. This will quickly overwhelm Windows, resulting in slow starts (Windows tries to check each device point you have ever connected to see if there is a device there!) and bfgminer locking up on launch once the number of virtual COM ports exceeds 500.
Is there a solution? Yes.
First unplug all your BEs and hubs.Launch cmd.exe
Then run the folloing in the command window:
set DEVMGR_SHOW_NONPRESENT_DEVICES=1
Next launch device manager from the same window by executing
Finally, in the Device Manager check View->Show hidden devices
Clean-up time.
Expand "Universal Serial Bus controllers" and delete (hit 'Del' key and confirm with enter) all devices with greyed-out icon (this section will contain your hubs). Do not delete driver software (leave the checkbox in the prompt unmarked)
Repeat for "Universal Serial Bus devices"
And finally for "Ports (COM & LPT)"
Optionally go through the other sections and delete greyed out devices: your Windows will be more stable and start faster. Don't worry, if you plug a device at a later point, it will get re-added to the list.
Done?
Now, plug in all your hubs (without BEs) in the topology you wish to use. Wait for them to be initialised.
Then plug your BEs.
Enjoy cleaner and more stable Windows.