Hi,
I also experienced a change in Hx Edit"s ability to detect device after getting to the 2.80 version. I discovered that having a USB mouse in one of my 3 USB ports was casuing earlier versions of Hx Edit to have problems, so I had already removed the USB mouse to get to this point. What I found was ...by changing to the 1st USB port my computer sees, the Hx Edit magically gained stability and I was finally able to upgrade the rest of the way to 2.81.
ALSO...I rebooted my computer after going to 2.80 and this seemed to help. The final update was performed using Line6 Update 1.18 and 2.81 Hx Edit. Anything else got errors.
In your particular case I suspect that your audio interface unit is plugged into a USB port that the Line6 software would like to use?
Good Luck. For Line6 admins, I strongly suggest that someone write up an Update FAQ that includes the simple fact that one cannot seemingly update from any version directly to the latest version e.g 2.81 without using the relevant Hx Edit and Line6 Update version. I started on version 2.51 and it took me two days to figure out the exact versions necessary AND to realize that my USB mouse was interfering with both the Line6 Update and Hx Edit programs despite the fact that it is not a "UsB hub"
I am good now, but it was quite an experience for someone who used to beta test Gigastudio software to find out there were still other ways to be experience software joy.