Yes i had a same issue 2 i had 1 TB from EGO
it was disconnecting and reconnecting hole time.
I updated every thing and still
didn’t solve.My sisters 1 TB External Drive did work good on my USB.
So the problem was the 1 TB was not compatible with windows 8. So try a difference External drive.
If its still the same problem try this:
It could be the ur External drive that doesn't work but try first to update al your Hardware. (make sure you have downloaded the driver from ur External drive)
Look at your ASUS update programs if you have already updated everything.
You can update it by going to the website of ASUS and select your model and you can see if you have the latest drivers.
And the USB drive update I had was from the programme DRIVER GENIUS but diden't work but you can try.
ACER PREDATOR G9-791 |Intel Core i7-6700HQ |16 GB RAM |GTX970M 3GB |FULL HD | 750GB SSD | Samsung 850 PRO & 2X M.2 SSD RAID 0
G75VW |Intel Core I7-3610QM |24GB RAM |GTX670M 3 GB |FULL HD | 526GB SSD | Samsung 840 EVO & 850 PRO
GL552VW |Intel Core i7-6700HQ |12 GB RAM |GTX960M 3GB |FULL HD | 256GB SSD | Samsung