How to set an external hard drive to not be bootable

bootexternal hard driveusb-storage

When I connect my external hard drive to my PC, it tries to boot from it but is unable to do so because there is no OS installed. And rightly so, I only want to use it for dumb storage.

How can I set it so that it's not bootable? I regularly boot from other USB drives, so I don't want to change my boot order in the BIOS.

Modern BIOSes generally move on to the next device in the list according to the boot order specified, if the previous device is not bootable. If that's not happening here, use diskpart or GParted to ensure the USB HDD's partition is not set to be active. For diskpart follow the steps below but use the inactive command instead as shown by the command's help screen (take care to select the proper disk and partition!):