Do external hard drives attached to iMac's (Thunderbolt or USB 3.0) turn off when iMacs shut down or go to sleep?

Hello... I am very interested in buying my first iMac (First Apple PC). As I want to get one with an SSD only (256G), storage might be an issue.

Therefore, If I buy an external hard drive enclosure, do i have to keep turning it on and off when plugged into an iMac? Does the iMac automatically power down external hard drives? I haven't decided on a specific brand yet, or whether I need one that is powered or non-powered?

Thank you.


1 Answer from the Community

  • Hi Andrew

    I'm relatively new to the wonders of Mac technology, as i've only recently purchased a Macbook Pro a couple of months ago.
    I use it with an external HD which has all my media on it, minus music.

    I can confirm that battery life does decrease when the HD is still attached. This is even when the Macbook is in sleep mode and you have selected the 'Eject' option and it disappears from your desktop.

    I found this quite unusual, but it definitely does still use power. Not sure why.

    So to preserve battery life, after you have ejected the drive in the correct manner, physically eject it from your computer.

    Hope this helps!

    Best regards


    • Answered by Steve R from Gravesend
    • 17-Nov-2014