Launch Disk Utility and select the unmounted drive from the left side, unmounted drives will be grey.Remounting is just a matter of doing the following: If you choose this option, you can remount the drives again using the Disk Utility app to regain file system access. Or, using Disk Utility to unmount the drive.Dragging the external disk to the Trash.You can unmount a hard disk without physically detaching it by either: The downside to this approach is you’ll have to manually mount the drive when you do want to use it, and Time Machine backups will not take place when the drive is unmounted. Option 2) Unmounting Hard Disks When Not in UseĪnother solution is to simply unmount the external hard disks when they’re not in use, this will also prevent them from spinning up at random or when a open/save dialog box appears.

If you leave your computer turned on all the time rather than sleeping or shutting down, this is probably not the best option to use.

For that reason it’s best to use this option sparingly unless you don’t mind the possibility of a shorter drive life for both the internal and external hard drives.

Click on the “Power Adapter” tab and uncheck the item labeled “Put the hard disk(s) to sleep when possible”īy checking this option the external (and internal) hard disks will not spin down to sleep while not in use, this will completely prevent the drive waking lag time and beachballs, however it can also reduce the lifespan of traditional spinning hard disks.

Launch System Preferences from the  Apple menu and click the “Energy Saver” panel.

There are a couple possible remedies for this problem, read on to understand the pros and cons of both choices. That drive spin up time is waking the disk from its sleep state which can lead to some pretty serious system dragging even on the fastest Macs, and as a result you’ll often encounter a lengthy beachball cursor that slows down a Mac as you wait for the external drive to arise from sleep.

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