How to Set an External HDD to Active

By Amanda Rumble

An external hard disk drive is portable and connects to your computer via a USB cable. When your computer has multiple hard drives, one of the hard drives or partitions on the hard drive must be marked as active in order for an operating system to boot. Set both internal and external hard drives as active through the built-in Computer Management Tool in Windows 7.

Click "Start" (the Windows-logo button on the lower-left-hand corner of the screen) and select "Control Panel" from the menu.

Click the "System and Security" option.

Scroll to the bottom of the page and select "Administrative Tools."

Double-click "Computer Management" to open the various management options.

Select "Disk Management" located on the left-hand side to display a listing of your hard drives and their statuses.

Scroll through the list of your hard drives and right-click on your external hard drive.

Select "Mark Partition as Active."