Computer Fails to Boot When External Drive Is Connected

“I have an external USB hard drive. When it is connected, my PC won’t boot. If I disconnect the drive, the PC boots just fine. If I then connect the external drive, it works just fine too. Any idea why this happening, and how it can be fixed?”

Yes, this issue can be fixed without much trouble. With little tweaks in the operating system configurations and with some changes on how you handle your computer can definitely solve the problem. Now, let’s see the causes and fixes for ‘computer failing to boot when external drive is connected’ issue.

Possible Causes for Boot Failure When an External Drive Is Connected

The operating system may get confused, when you connect the external hard drive to your device before turning it on leading to boot failure. It can also be because of computer’s configuration or the external hard drive conflicting with the operating system’s boot procedure.

Below are some methods that you can work around to fix an external HDD that’s stopping the operating system to boot.

Here we are talking about system boot failure. But in case you have booting problem with external drive, you can find out what are the causes and solution for external hard drive wont boot up issues.

Let’s begin with the fixes.

Plug It After Turning On the System

The external hard drive need not be plugged in before you turn on the computer, unless you are booting from it. One of the fixes for boot failure issue is to unplug the external HDD before turning on the computer and plug it in after the OS has loaded.

Boot Through BIOS

The PC’s BIOS can alter some of the issues that’s stopping your computer to boot when an external hard drive is connected.

To access to BIOS mode from Windows 7 – turn on your PC and in the first screen that appears, look for the message that shows you which key to press to enter into BIOS. The notification can be something like this: BIOS settings: Esc; Setup=Del or System configuration: F2 or Press DEL to enter SETUP.

For Windows 8 – go to Settings > Change PC Settings,” click General > Advanced Startup Restart Now. Then Select Troubleshoot > Advanced Options > UEFI Firmware Settings and Restart your computer to boot into BIOS.

Windows 10 – press and hold “Power Button” for 5 or more seconds to turn-off your PC. Now ON the PC and as soon the logo appears, press F2 key immediately.

Disabling USB Legacy Support

Disabling USB Legacy Support may help your computer boot correctly. USB Legacy Support allows the PC to use USB-peripherals minus OS drivers and may result in system hanging upon boot when an external HDD is plugged in. You can turn off USB Legacy Support via BIOS. With the help of keyboard keys look through the menu until you find Legacy USB support and turn it off.

Change Boot Sequence

Your computer might have changed the boot order. Meaning, booting from USB devices might have been prioritized than from internal drives. While you are in BIOS, under the BOOT tab, search for “USB-HDD” or USB and with help of on-screen guide and arrow keys move it to the bottom of the list to fix the boot failure.

Remove hidden files

There may be some files in the root directory of external hard drive that are confusing the PC on boot. These files can be removed without any damages to the device. To see the hidden files, go to Control Panel > View tab, click on the radio icon next to Show hidden files and folders and press OK. Now go to File Explorer and delete all the hidden files in the root directory on the external hard drive.

All the above methods would make your computer to boot normally even if external hard drive is connected.