How to Keep a USB Active on a Macintosh in Sleep Mode

By Jason Taetsch

Set your Mac OS X external hard drives to sleep in order to save energy.
i external hardrive image by Photoeyes from

The sleep mode on your Macintosh helps your computer conserve energy by powering down certain parts of the computer's hardware while not in use. If you are transferring a large amount of files through your USB drive, you can adjust the settings in the "System Preferences" to put parts of your Mac to sleep while keeping your USB drive active. While sleeping, the display will go dark but the USB drive will continue to send and receive data from your hard drive.

Step 1

Connect your flash drive, MP3 player, scanner or printer to your USB drive.

Step 2

Click the "Apple" menu and click the "System Preferences" entry in the list. Click the "Energy Saver" option. Slide the "Display Sleep" switch to the amount of minutes you want the computer to wait before putting the computer to sleep. Drag the "Computer Sleep" slider to the "Never" position.

Step 3

Press "Control," "Shift" and "Eject" at the same time to put the computer to sleep. The display will go dark but the USB drives will continue working.

Step 4

Press any key on the keypad to wake the computer from sleep.