EC27250 usb 3.0 port

when I plug a powered 8Tb Seagate hard drive formatted as FAT into the usb 3.0 port on my Dell 27 All-in-One EC27250 it locks the mouse and disables the touch screen function. Seagate has replaced the original hard drive but the same issue is arising. I have done the usuual in terms of checking the drive works on other PCs and used different usb cables.

My current workaround is plugging the drive into a usb 2.0 extender connected to the Dell usb 3.0 port which works but I have forfeited the data transfer speed which is no more than 35Mb/s. Anyone any idea why this is happening and how to fix it as the Seagate drive is clearly incompatible with the DEll usb 3.0 port in some way or other.

Seagate have been helpful in replacing the drive but Dell simply states that it is a third party issue and as such they are unable to help. Can anyone suggest what is happening and how it might be resolved?