If the USB drive is powered from the Humax, e.g. it doesn't have a separate mains power supply, it may be causing a problem because it requires too much power, does it work if you plug the USB HDD into the Humax after the Humax has powered up?
You only have few options, you could try the the other USB socket just in case it supplies more power, supply power from the separate supply and an adapter cable or as you say continue to unplug it during boot-up of the Humax
So that I can avoid a similar issue what is the make and model of the USB drive?oh well I will unplug it each time.
A powered USB port expander might help.
So that I can avoid a similar issue what is the make and model of the USB drive?
Is this a USB3 drive? A USB2 hub should be OK because the drive has to fall back to USB2 for the Humax, but make sure the powered hub is able to supply USB3 current.
See notes HERE (click).
According to Google it should be OK power wise with a usb2 hub. I say should as the combination of the hub and the devices makes hub selections a bit of a lottery at best in my experience!
v63600-C 1TB DC+-5V ~ 1.0A 11/11Toshiba CorporationMade in China
the USB hub has done the trick, I can now reboot the humax without unplugging the usb drive!
At 4 Quid it's a brilliant solution, I've seen 'converter cables' designed to allow the addition of a separate power supply (not supplied) cost more than that ! !