I am regularly using 8TB external drives.
My system is a U9-H. I have a powered USB hub attached to it. The USB hub has 5 ports. I have a Dual SATAdock plugged into the hub, where I often have 2 8TB drives installed, plus I usually have 2 2TB portable USB drives plugged in, for a total of 20TB of external storage.
The key here is to connect all this storage through a SINGLE USB port.
If you plug any other storage into any other USB port on the U9-H it gets very confused and refuses to work properly. The only other thing I have plugged in is the remote dongle.
I hope that helps someone.
A further FYI
. I had no issues at all directly using the U9-H's USB ports with 3 x external 8TB HDD's
that have their own power supplies. (When I was using that set up I connected the a3's dongle to the OTG adapter/port lol
.) It all worked just fine. (I've since purchased dedicated NAS's so I'm no longer set up as such.)
What my U9-H didn't like & that seems to be the case with yourself & others as well, was using
unpowered HDD's (& even a couple of flash drives) without
properly unmounting them first or swapping USB ports on the U9 by direct connection.
Of course, the specific make/models of the HDD's &/or their enclosures could also play a big part too. I was using quality hardware from WD & Seagate.
From my experience, what's been posted before about these problems & the info here....
....
In summary, it seems that if you're using multiple
powered HDD's you could be able to use them as normal directly connected to the USB ports on the U9 & a hub may not be required. If using multiple
unpowered HDD's, then use a powered USB hub to connect them all through a single port.
