You can make Mac OS X Lion more energy efficient by configuring parts of your Mac to go into sleep mode automatically when you are not using them. Sleep mode means that your display or your Mac is in a temporary low-power mode. This saves energy on all Macs, and also saves battery power on a. Troubleshooting sleep in OS X Several settings and system features govern the sleep mode in OS X and can prevent normal system sleep if either in use or used incorrectly. By Rob Griffiths. After you launch Terminal, the first step is to determine which sleep mode your Mac is currently using (in case you wish to go back to it).

Sleep mode (or suspend to RAM) is a low power mode for electronic devices such as computers, televisions, and remote controlled devices. These modes save significantly on electrical consumption compared to leaving a device fully on and, upon resume, allow the user to avoid having to reissue instructions or to wait for a machine to reboot. Many devices signify this power mode with a pulsed or red colored LED power light.

Computers[edit]

In computers, entering a sleep state is roughly equivalent to 'pausing' the state of the machine. When restored, the operation continues from the same point, having the same applications and files open.

Sleep[edit]

Sleep mode has gone by various names, including Stand By, Suspend and Suspend to RAM. Machine state is held in RAM and, when placed in sleep mode, the computer cuts power to unneeded subsystems and places the RAM into a minimum power state, just sufficient to retain its data. Because of the large power saving, most laptops automatically enter this mode when the computer is running on batteries and the lid is closed. If undesired, the behavior can be altered in the operating system settings.

A computer must consume some energy while sleeping in order to power the RAM and to be able to respond to a wake-up event. A sleeping PC is a case of a machine on standby power, and this is covered by regulations in many countries, for example in the United States limiting such power under the One Watt Initiative, from 2010. In addition to a wake-up press of the power button, PCs can also respond to other wake cues, such as from keyboard, mouse, incoming telephone call on a modem, or local area network signal.

Hibernation[edit]

Hibernation, also called Suspend to Disk on Linux, saves all computer operational data on the fixed disk before turning the computer off completely. On switching the computer back on, the computer is restored to its state prior to hibernation, with all programs and files open, and unsaved data intact. In contrast with standby mode, hibernation mode saves the computer's state on the hard disk, which requires no power to maintain, whereas standby mode saves the computer's state in RAM, which requires a small amount of power to maintain.

Hybrid sleep[edit]

Sleep mode and hibernation can be combined: the contents of RAM are first copied to non-volatile storage like for regular hibernation, but then, instead of powering down, the computer enters sleep mode. This approach combines the benefits of sleep mode and hibernation: The machine can resume instantaneously, but it can also be powered down completely (e.g. due to loss of power) without loss of data, because it is already effectively in a state of hibernation. This mode is called 'hybrid sleep' in Microsoft Windows other than Windows XP.

A hybrid mode is supported by some portable Apple Macintosh computers,^[1] compatible hardware running Windows Vista or newer, and Linux distributions running kernel 3.6 or newer.

ACPI[edit]

ACPI (Advanced Configuration and Power Interface) is the current standard for power management, superseding APM (Advanced Power Management) and providing the backbone for sleep and hibernation on modern computers. Sleep mode corresponds to ACPI mode S3. When a non-ACPI device is plugged in, Windows will sometimes disable stand-by functionality for the whole operating system. Without ACPI functionality, as seen on older hardware, sleep mode is usually restricted to turning off the monitor and spinning down the hard drive.

Microsoft Windows[edit]

Microsoft Windows 2000 and later support sleep at the operating system level (OS-controlled ACPI S4 sleep state) without special drivers from the hardware manufacturer. Windows Vista's Fast Sleep and Resume feature saves the contents of volatile memory to hard disk before entering sleep mode (aka Hybrid sleep). If power to memory is lost, it will use the hard disk to wake up. The user has the option of hibernating directly if they wish.

In older versions prior to Windows Vista, sleep mode was under-used in business environments as it was difficult to enable organization-wide without resorting to third-party PC power management software.^[2] As a result, these earlier versions of Windows were criticized for wasting energy.^[3]

There remains a market in third-party PC power management software for newer versions of Windows, offering features beyond those built into the operating system.^[4][5][6] Most products offer Active Directory integration and per-user/per-machine settings with the more advanced offering multiple power plans, scheduled power plans, anti-insomnia features and enterprise power usage reporting. Vendors include 1E NightWatchman,^[7][8] Data Synergy PowerMAN (Software)^[9] and Verdiem SURVEYOR.^[10]

macOS[edit]

Sleep on Macs running macOS consists of the traditional sleep, Safe Sleep, and Power Nap. In System Preferences, Safe Sleep^[11] is referred to as sleep. Since Safe Sleep also allowed state to be restored in an event of a power outage, unlike other operating systems, hibernate was never offered as an option.

In 2005, some Macs running Mac OS X v10.4 began to support Safe Sleep. The feature saves the contents of volatile memory to the system hard disk each time the Mac enters Sleep mode. The Mac can instantaneously wake from sleep mode if power to the RAM has not been lost. However, if the power supply was interrupted, such as when removing batteries without an AC power connection, the Mac would wake from Safe Sleep instead, restoring memory contents from the hard drive.^[12]

Safe Sleep capability is found in Mac models starting with the October 2005 revision of the PowerBook G4 (Double-Layer SD^[vague]). Mac OS X v10.4 or higher is also required.^[13]

In 2012, Apple introduced Power Nap with OS X Mountain Lion (10.8) and select Mac models.^[14] Power Nap allows the Mac to perform tasks silently, such as iCloud syncing and Spotlight indexing. Only low energy tasks are performed when on battery power, while higher energy tasks are performed with AC power.^[15]

Unicode[edit]

Because of widespread use of this symbol, a campaign was launched to add a set of power characters to Unicode.^[16] In February 2015, the proposal was accepted by Unicode and the characters were included in Unicode 9.0.^[17] The characters are in the 'Miscellaneous Technical' block, with code points 23FB-FE.^[18]

The symbol is ⏾ (⏾)—defined as 'Power Sleep Symbol'.^[18]

See also[edit]

No Sleep For Mac Os X 10.10

References[edit]

1. ^'About safe sleep'. Apple Inc. Archived from the original on April 2, 2012.
2. ^'PowerMAN PC Power Management Software Documentation'. www.datasynergy.co.uk.
3. ^'EcoGeek - How Windows XP Wasted $25 Billion of Energy'.
4. ^'Power Management Software for Windows Workstations'.
5. ^'Activating Power Management: Commercial Software Packages'. www.energystar.gov.
6. ^The Headmasters' and Headmistresses' Conference. 'HMC: A Practical Guide to Sustainable Building for Schools'. Archived from the original on 2012-03-15.
7. ^'PC Power Management Solutions'. IT Managers Inbox. May 26, 2009.
8. ^'Why use software NightWatchman to turn your PCs off?'.
9. ^'Keeping IT Clean: energy and the networked computing environment'. projects.oucs.ox.ac.uk.
10. ^'1E upgrades NightWatchman, seeks to bring powermanagement to SMEs: Competitive landscape'(PDF). Archived from the original(PDF) on 2011-07-07.
11. ^'OS X Lion: What is safe sleep?'.
12. ^'What is safe sleep on Mac?'. Apple Support.
13. ^'How to Safe Sleep (Hibernate) Your Mac - AndrewEscobar.com'. web.archive.org. January 5, 2008.
14. ^LLC, Kyle Media. 'What is Power Nap? Power Nap Macs & Hack Possibilities @ EveryMac.com'. www.everymac.com. Retrieved 2017-02-02.
15. ^'How Power Nap works on your Mac'. Apple Support. Retrieved 2017-02-02.
16. ^'Unicode Proposal 14009 Power Symbol'(PDF). Unicode. Unicode Consortium. Retrieved Dec 23, 2015.
17. ^West, Andrew (2016-01-10). 'What's new in Unicode 9.0?'.
18. ^ ^ab'Unicode Chart - Miscellaneous Technical - Range: 2300–23F'(PDF). 2016-06-22.

Summary: In this blog, we’ll share a variety of D-I-Y methods on how to resolve external hard drive sleep problems on Mac.
The 7 useful methods you will learn are listed down as:
1. Reconnect the External Hard Drive
2. Reboot Your Mac
3. Tweak macOS Sleep Setting
4. Reinstall Hard Drive Software
5. Install the Latest Version of macOS
6. Repair the External Hard Drive
7. Erase the External Hard Drive
And don’t worry about your data stored on Mac external hard drive having the ‘sleep problem’. Download the free trial of Stellar Data Recovery Professional for Mac. Recover the data from hard drives on Mac systems running on macOS Catalina.

Methods to Fix External Hard Drive Sleep Issue

1. Reconnect the External Hard Drive

Activate your sleeping external hard drive by reconnecting it to your Mac. The drive will now be visible in Finder, and you can access the storage medium for read-write operation.

2. Reboot Your Mac

With the external hard drive connected, reboot your Mac to fix any system misconfiguration, error, or otherwise. It’ll revive the inactive external storage drive, and you can use it as usual.

3. Tweak macOS Sleep Setting

To resolve Mac external hard drive sleep issue, correct the default sleep setting from the Energy Saver window. Steps are as follows:

1. Go to Apple menu > System Preferences > Energy Saver.

No Sleep For Mac Os X 10.7

2. From the Energy Saver window, deselect “Put hard disks to sleep when possible” checkbox in Battery and Power Adapter panel.

No Sleep Mac Os X

Now, your external hard disk will remain active. This setting won’t affect SSD, as it doesn’t have any moving component.

4. Reinstall Hard Drive Software

Incompatible hard drive software can prevent macOS from performing correctly. So, uninstall the driver from your Mac. Next, visit the manufacturer’s website and download the latest, compatible driver. Now, install the driver to fix the external hard drive sleep problem.

5. Install the Latest Version of macOS

Bugs in Mac OS X or macOS may also result in the external hard drive sleep problem. Update or upgrade the operating system to the latest version to patch up the issue. Steps are as follows:

1. Go to Apple menu > System Preferences > Software Update.
2. If updates are available, click the Update Now button.

For macOS High Sierra, Sierra, El Captain, or an earlier version, perform the following:

1. Open App Store then click Updates from the toolbar.
2. Click the UPDATE ALL button to download and install the available updates.

If you have Mac OS X Lion or Snow Leopard, execute the following:

• Go to the Apple menu > Software Update.

6. Repair the External Hard Drive

No Sleep For Mac Os X 10.13

To fix any unknown hard drive issues, try repairing the Mac storage drive. Steps are as follows:

1. Press Command + Space Bar to open Spotlight.
2. Type “disk utility” then press Return to open the Disk Utility app.
3. Select the external hard drive from the left panel and click the First Aid tab.
4. Click Run to initiate the drive verification and repair process.

Or else, use file system consistency check (fsck) command in Single User Mode as explained next:

1. Start or restart your Mac then immediately press-hold Command + S keys.
2. At the command line, type /sbin/fsck –fy then press Return.
3. Let the command complete the verification and repair process.
4. Rerun the command multiple times if required until the drive check is OK.
5. Type reboot then hit Return.

No Sleep For Mac Os X 10.8

Read More: Should you trust Disk Utility’s First Aid or fsck?

7. Erase the External Hard Drive

Create a backup of your external hard drive before performing this fix. Once you have backed up all your valuable data, perform the following steps:

1. Open Disk Utility.
2. Select the external hard drive from the left panel then click the Erase tab.
3. Specify the name, format, and other details then click Erase.
4. Once the erase operation completes, restore the backed up data to the drive.

Conclusion

We hope this post will help you resolve your external hard drive sleep problem. Troubleshoot by reconnecting the external hard drive or rebooting your Mac. Go to Energy Saver window from System Preferences and ensure you deselect “Put hard disk to sleep when possible” checkbox. If the issue persists, try reinstalling hard drive software. Also, install the latest version of macOS.

In case the issue is with your external storage drive, repair the drive by using First Aid or fsck command. As a last resort, back up the drive, erase, then restore the backed up data. In any accidental data loss scenario, use the best Mac data recovery software to salvage your lost data.