How to Detect External Hard Disk Drives

An external hard drive is a regular computer hard drive enclosed in a portable casing. Many external hard drives are powered by an external power supply, while some are small enough to be powered from the computer's USB port. When an external hard drive is connected, the files on the computer can be copied and transferred between the computer and drive. Files on the drive can also be accessed directly on the computer and also moved to the computer's built-in hard drive. Detection of the drive occurs when the drive is plugged into the computer.

Turn on the computer and wait for the desktop or home screen to appear. Log in to Windows or Mac OS X if prompted.

Plug the USB cord of the external hard drive into an available USB port on the computer. If the hard drive is self-powered, plug the power supply into a wall outlet or surge protector. Verify that the power switch on the hard drive is switched to on if it has a switch.

Wait a few seconds for the computer to detect the hard drive. View the desktop screen and look for an icon of a hard drive, or if you previously named the external drive, look for an icon matching the name. By default, some external hard drives will display as "No Name" or "External Drive" or "USB drive."

Look for a popup notification on the desktop screen if you do not see an icon. The notification indicates that the drive is detected. Click it to access the hard drive.

Step 5

Click on "Start" followed by "My Computer" and look for the labeled drive or a drive such as "E:/" or "F:/." Double-click it to access the drive if it isn't visible on the desktop. On Macs, click on the "Finder" icon in the dock and locate the drive under the "Devices" heading.

Leave the hard drive connected to the computer and restart the computer if the drive is not detected the first time.

If the drive still isn't detected and the drive came with a CD, insert the CD into the computer and run the "Driver Installation" program to provide the computer with the needed drivers to recognize the device.

Connecting a hard drive formatted for Windows to a computer running Mac OS X can prevent access to the contents or even cause files to be damaged or erased on the drive if the computer tries to automatically format the drive. Connecting a drive formatted for Mac to a Windows computer results in a similar situation.