USB and upgrading ESX/ESXi

If you are using USB devices on your virtual machines with ESX/ESXi (for instance using a USB over network hub with vSphere), you know that you need to install a USB concentrator device for your USB device to be recognised in your VM.

Now if you upgrade to 4.1 (for instance, to get USB passthrough connectivity), you need to reinstall said concentrator.

To do so: 

Delete all USB devices in the VM settings.

Then delete the concentrator.

Close the settings, wait for it to finish, then reopen settings, add your concentrator. Repeat the process with your USB device.

Tada, USB is now fully functional.

If you don't do so, your USB device will show up in your VM, but won't be fully usable.