How to resolve PC hangs caused by external USB HDD?
This may happen if your PC is using the old BIOS system. This problem is usually not present on computers that use a modern UEFI system.
Solution #1
What you can to do in this case is enter your BIOS setup program and disable the legacy support for UMS (USB Mass Storage) devices. This option may or may not be available in your BIOS setup program. It may also be labeled differently in different BIOS setup programs.
To disable this option on an Award BIOS motherboard, do the following.
- Boot up or reboot your PC.
- Press DEL to enter BIOS setup.
- Go to Advanced Peripherals.
- Select USB Storage Function.
- Change its value to Disabled.
- Press ESC.
- Press F10 to save changes and exit.
- Confirm with Enter.
Your PC should now thank you and boot up normally without hanging itself with the tethered USB HDD around its neck.
Note! Disabling the USB Storage Function will prevent your PC from booting from USB devices. If you ever need to boot from USB device, for example to install an operating system, be sure to enable this function before you trying booting off of the USB device.
I have tested and confirmed this procedure using Seagate Backup Plus Desktop HDD (4 TB, USB 3.0) and Award BIOS 6.00PG on a Gigabyte GA-X38-DQ6 motherboard.
I have also tested a second HDD of the same brand and model on a Gigabyte GA-MA with the same results and findings.
Solution #2
Another thing you can do is try connecting the HDD to a different USB port.
- Power off PC.
- Disconnect all USB devices including the keyboard and mouse.
- Connect the HDD to USB port 0.
- Power on PC and check if it hangs.
- If it hangs, power off PC.
- Connect the HDD to USB port 1.
- Power on PC and check if it hangs.
- Repeat until you find a port at which the PC no longer hangs.
Note! This solution is theoretical and untested.
The idea behind this is that some USB port(s) may be used by a different USB controller. A different host USB controller may have better compatibility with the USB controller of the external HDD. You can also check your PC or motherboard manual to see what chip controls what USB port. You may have to enable it inside BIOS setup first before you can use it.
Cause
The exact cause of this odd behavior is unknown to me. But it seems that it has to do with the inner workings of BIOS systems. Old tech and new tech don't mix all too well. While the HDD is backwards compatible with USB 2.0, it may not be compatible with USB 1.1 hosts which is what the BIOS may be enforcing for UMS class devices when the mentioned option is set to Enabled. It may be a compatibility issue between certain USB controllers of the PCs and the drives.
Whatever the cause may be, I hope this answer proves helpful to other users who are using old BIOS systems.