I have a question similar to a previous one about ejecting before shutting down.

Is it necessary or recommended practice to eject external drives before putting a Mac to sleep, whether it be via an explicit sleep command (e.g., from the Apple menu or other equivalent means), if Energy Saver puts the Mac to sleep, or the closing of a lid on a laptop Mac?

Edit: To add a clarifying point, I do not plan to physically disconnect the drive before waking the Mac from sleep?

  • How does this differ from the previous one?
    – mmmmmm
    Mar 28 '13 at 12:58
  • This isn't a dupe. It's asking about sleeping, whereas the linked question asks about logging out, restarting, and shutting down. They're distinct operations.
    – duozmo
    May 11 '14 at 4:49
  • Whoever marked this as a duplicate obviously can't be bothered to actually read the two questions. Restarting and shutting down have almost nothing in common with sleeping, at least for purposes of ejecting drives.
    – iconoclast
    Jan 22 '15 at 21:40

It's neither necessary nor recommended (at least from what I've read).

When you put the Mac to sleep, it will try and also put the external drive to sleep, thus parking its heads and turning off the drives. It won't eject it, however, so you can use it as soon as you wake your Mac again without having to mount it.

The benefit is that you don't have to worry about mounting it, as in most cases this would involve turning the drive off and on again, reconnecting the plug, or using diskutil from a Terminal—quite time consuming. Since I use my drive for Time Machine, I don't want to have to think about connecting it every time I wake my Mac.

The only downside I see is that you could accidentally plug the drive out. In that case, the Mac will wake up, and show you the error about a drive being disconnected without properly ejecting it. Since all data is written to the drive before going to sleep, this shouldn't cause any data loss though.

All in all, it's much more comfortable to just keep the drive mounted.

  • Do you have a source for "When you put the Mac to sleep, it will try and also put the external drive to sleep, thus parking its heads and turning off the drives."?
    – Jason
    Mar 22 '13 at 18:00
  • 1
    Yes, my external drive :)
    – slhck
    Mar 22 '13 at 18:02
  • Fair enough. I had observed said behavior on my external drive as well, but since it houses my iTunes and Aperture libraries, I want to be extra cautious (yes, I have backups).
    – Jason
    Mar 22 '13 at 18:11

Maybe it's not necessary, but I would recommend ejecting drives before going to sleep, at least on a MacBook. It has just too often happened to me that I had to leave in a rush and then I didn't find the time to open the lid, eject the drives and putting closing it again – I just grabbed the Machine, pulled all cables and left – and that can be a quite bad idea, especially when working with FireWire connections...


I usually don't eject external drives before sleeping my machine. I went so far as closing my laptop, thus put it in sleep mode, wait a couple of seconds for it to enter sleep mode, then yank out the drive's USB cable. Later on, when the laptop wakes, it does not see the hard drive, but things will go on normally.


Yes, before putting the machine to sleep, I make sure quit all applications which use the external drive. Here is a common scenario for me:

  1. At the office, close the laptop to put it in sleep mode
  2. After the laptop is in sleep mode, yank the USB cable to remove the hard drive
  3. At home, re-attach the hard drive
  4. Wake the machine up

Everything should work as normal now.

  • This is a problem if an active application is using the drive when the machine is put to sleep. I wouldn't recommend physically disconnecting the drive while asleep.
    – zwerdlds
    Mar 22 '13 at 17:37
  • I agree with @zwerdlds. See my update.
    – Hai Vu
    Mar 22 '13 at 18:11
  • If you remove the drive while the laptop is sleeping, it should wake up, actually…
    – slhck
    Mar 22 '13 at 18:13
  • @slhck The application would still be unable to react to the drive's ejection. The problem isn't that the computer doesn't "know" about the ejection, it's the propensity to corrupt data. I would never advocate disconnecting a disk without ejecting first, even in a Windows environment (which doesn't whine as much as the Mac OS). Active applications can also include background applications and daemons which you have no knowledge of.
    – zwerdlds
    Mar 22 '13 at 18:15

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