Hi there.
This is my first time on this forum so please excuse me if this is in the wrong area, so to speak.
My problem is I recently configured my USB hard drive to be used with the Xbox 360 and it worked like a charm. I was soon getting the Borderlands 2 DLCs onto my Xbox
However, I needed to use the USB for college work so, making sure no files were on it, I ran a Quick Format on the PC.
Now that I’ve formatted it on the PC, I am no longer given an option to configure it for Xbox use and, when I format the hard drive ON the Xbox, it ends up giving me the USB’s complete space of 931GB, but Horizon can no longer recognise the USB.
There were recent updates for Xbox360 and Horizon. It sounds like you already have the Xbox update and need to update Horizon now. You can download the latest version from this link: https://www.horizonmb.com/client/v2/latest.php