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Sleep or Shutdown dialog box on green battery icon

Should You Shut Down Your Mac or Let It Sleep Every Night?

One question that new Mac users often ask is whether they should shut down their computers at the end of the day or just let them sleep. The quick answer is that sleep is better for your Mac, and in today’s Tech Tip we’ll show you why it’s better to just let your Mac go to sleep than shut it down each day.


Shutting Down Your Mac Keeps It From Running Maintenance Tasks

The main reason for letting your Mac sleep instead of shutting it down is that your Mac can’t perform maintenance tasks during the night if you shut it down. macOS does a lot every night while your Mac isn’t being used and it is “sleeping”. Apple actually has a term for this sleep mode — “Power Nap”. 

So what does it do during a Power Nap?

A lot.

  • Mail receives new messages.
  • Contacts keep up to date with changes made on other devices.
  • Calendar receives new invitations and calendar updates.
  • Reminders keep up to date with changes made on other devices.
  • Notes keep up to date with changes made on other devices.
  • Documents stored in iCloud keep up to date with changes made on other devices.
  • Photo Stream keeps up to date with changes made on other devices.
  • Find My Mac updates the location of the Mac, so you can find it while it’s asleep.
  • VPN on demand continues working so that your corporate email updates securely. (Power Nap supports VPN connections that use a certificate to authenticate, not VPN connections that require entering a password.)
  • Mobile Device Management can remotely lock and wipe your Mac.

If your Mac is plugged into AC and taking a Power Nap, it will also do the following:

  • Software updates are download.
  • Mac App Store items (including software updates), download in the background.
  • Time Machine performs backups.
  • Spotlight performs indexing.
  • Help Center content updates.
  • Wireless base stations can wake your Mac using Wake on Wireless.

While your Mac appears to be sleeping, it’s actually doing a lot! The good part of all of this is that when you get back behind the keyboard and you’re ready to start working, your Mac wakes up quickly from sleep and is ready to get to work. There’s no need for it to go through the startup procedure, and it has already done all of the maintenance jobs it needs to do, so it’s ready to roll. 

Mac users new and old often say that their Macs are running slowly, and when asked they usually say that they’re shutting down the Mac every night. It’s not surprising that the machines seem slow, as the Mac needs to run through all of the maintenance tasks it should have been doing while sleeping.


What Macs Support Power Nap?

Most Macs built since the early 2010s support Power Nap:

  • MacBook (Early 2015 and later)
  • MacBook Air (Late 2010 and later – requires OS X Mountain Lion v10.8.2 and later)
  • MacBook Pro (all models with Retina display)
  • Mac mini (Late 2012 and later)
  • iMac (Late 2012 and later)
  • Mac Pro (Late 2013)

[UPDATE]
Due to the nature of Apple’s “always-on” silicon, M1 Macs do not have (or need) the Power Nap feature.


How Do I Enable Power Nap?

Owners of any of the Macs listed above should have Power Nap enabled by default. To make the Mac “go to sleep”, you can select “Apple menu > Sleep” from the menu bar, close the screen on a MacBook, MacBook Pro or MacBook Air, or move the cursor into what’s called a Hot Corner. 

Hot Corners are defined in the Desktop & Screen Saver system preference. In the lower right corner of the preference pane is a button for Hot Corners. Click it and a diagram showing the four corners of the primary display appears — each corner can have something assigned to it.

For example:

In the screenshot below, Put Display to Sleep has been selected for the lower right corner of the screen. Using the mouse or trackpad to place the cursor in the Hot Corner puts the device to sleep.

(Selecting a Hot Corner for putting a Mac to sleep)
Selecting a Hot Corner for putting a Mac to sleep

To make sure that your Mac has Power Nap enabled, go to “System Preferences > Energy Saver.” You’ll see the following preference pane, and just need to ensure that Enable Power Nap is checked.

Note: in macOS Big Sur, the Power Nap preference is found in “System Preferences > Battery.”

(Power Nap is enabled on the Energy Saver System Preference pane)
Power Nap is enabled on the Energy Saver System Preference pane (Battery Pane in Big Sur)

Am I Wasting Energy or Contributing to Climate Change By Not Shutting Down My Mac?

If you’re energy-conscious, you might be wondering if you’re wasting power by putting your Mac in Power Nap mode instead of turning it off. Well, it turns out that your Mac uses energy even when it is plugged in and turned off!

You can find out exactly how much power your Mac uses by visiting the Apple Product Environmental Report page. Near the bottom of this page, you can find environmental reports for every product Apple has made since 2009, and that information includes just how much power your device consumes.

For example:

I use a 27-inch iMac with a Retina 5K Display as my primary computer. When it is idle (that is, not actively performing any tasks) and the display is turned on, it uses 69.1W of power. Put that iMac to sleep, and it uses only 1.22 W of power. Turning the Mac all the way off, but keeping it plugged in, power use goes down to 0.24W. 

The difference in power consumption between sleeping the Mac and turning it off is only .98 W, meaning that over a year, I’m using an additional 5.7 kWh (kilowatt-hours) of power (assuming I actively use the Mac eight hours per day). At the current average residential electricity rate in my part of the country (12.04 cents per kWh), turning off that Mac each night would only save me about $0.69 per year. 

That 5.7 kWh also adds only about 5.68 lbs of CO2 to the atmosphere per year. Considering that burning a gallon of gasoline creates 19.6 pounds of CO2 and the average car currently gets about 22 miles per gallon, just driving .26 miles would create an equal amount of CO2 as is generated to power a sleeping iMac instead of turning it off.

• This post was originally published on March 1, 2019
• Most recently updated on April 9, 2021



Steve Sande
the authorSteve Sande
Contributing Author
Steve has been writing about Apple products since 1986, starting on a bulletin board system, creating the first of his many Apple-related websites in 1994, joining the staff of The Unofficial Apple Weblog in 2008, and founding Apple World Today in 2015. He’s semi-retired, loves to camp and take photos, and is an FAA-licensed drone pilot.
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86 Comments

  • You didn’t address additional wear and tear at all. A major problem with macs now is hard drive failure (which is unfortunately at least partially due to the adoption of afps) and combined with spotlight indexing and the other things you did mention put a lot more strain on your hardware. What I came hoping to find out is whether I can turn powernap off and how to. I didn’t need to be convinced it’s ok, I already know what I do and don’t like about it.

    • Be aware the Macs with Apple Silicon will disconnect Thunderbolt drives when they go to sleep. The disconnects are random, and they do not properly eject the drive. It’s best to check this box in Energy Saver:
      Prevent computer from sleeping when the display is off

  • If, for what ever purpose, I am easy cash at a desk I will merely get up and do some thing else. It may also be an indicator of how much money you will be betting for your sport. We don’t even attempt to be that way, we just are.

  • I used to have a MacBook Pro, but is now a vintage item. Since I retired, I opted for an iMac. It is a 2019, that I had an upgraded CPU installed in. The original iMac was Intel Core i5 and the MBP I took out of service was an Intel Pro i7. This was the main reason for requesting the upgraded CPU during the original order. It came with 8GB RAM, and MacOS 10.15, which was eat up issues that had me in recovery almost every time I came into my office. Then MacOS 11 “Big Sur” came out, and was hoping for better results. Had similar issues with 11.1, 11.2, and they finally got it more stable with 11.2.3. My big issue was coming back in the morning, to a iMac that had restarted with an issue. I am a fan of leaving the machine running, because of the overnight Maintenance things the MacOS does. Until I did a “Shift” Startup to this iMac a couple months ago, and the problems didn’t go away, but at least it not rebooting several times per day. I want to upgrade the RAM, but the iMac is not a MBP, and I now have a job that keeps me away from the computer to the point I don’t come in here much Monday thru Thursday. It is Friday night as I am writing this, and have off until Monday. I am a retired ACMT so I have replaced things in an iMac many times, even one like this before. I am not afraid of the repair or upgrade. Just too busy during my weeks.

    The main reason I decided to write a reply to this, was to make the point that the article is about MacBook Pro, and doesn’t inform the users that it is about that. I realized it after reading the first couple of replies from last week. There is NO Battery icon in the iMac System Preferences. I have an APC UPS, but it is not being allowed a connection to this iMac. There is a way to do that but disconnected after the iMac started shutting down as soon as the UPS went into Battery Mode. This was not the reason I got the UPS.

  • That would be great, but running Mojave on a 2015 MacBook Pro the fans run full speed all night long! Even after putting the computer to sleep. I’ll come back in the morning and I can hear them from down the hall. I’ve resorted to shutting down just to put an end to that. It wasn’t always that way. An SMC reset hasn’t made a difference. Repeated searches on the web have not identified the issue. Every once and awhile I’ll take another stab at it. In the mean time. She gets shut down.

  • Every computer I use has some sort of external storage. What about the ON vs Nap power consumption of ThunderBay external RAID storage?

  • I would suggest taking this advice with a grain of salt. Steve is evidently unfamiliar with Big Sur as there is no “System Preferences>Energy Saver” option in Big Sur. One must go to “System Preferences>Battery”, then use both the “Battery” and “Power Adapter” categories to accomplish his goal of enabling Power Nap.

    Additionally, Big Sur on my MacBook Pro 16 has many issues with “freezes” (forever spinning beachball, no keyboard response..cmd-option-esc does not respond). Shutting it completely off seems to clear things up enough to cure the problem for a day or so…by clearing memory and caches, I suppose. But it’s enough of an annoying problem that I’m considering going back to Catalina, which never had the problem I describe.

  • BTW, it is good to keep the desktop Mac plugged to the Mains, even when shut down, because otherwise the internal battery (a tiny one that keeps the clock, etc) drains out quickly.

  • One factor not considered in this analysis is Longevity. For those who like to buy a new Mac every few years this may not be a problem but for those that like their Macs to live forever, it might be. Logically, it seems to me leaving the Mac powered on even in sleep mode 24/7 would have a negative effect on longevity. Something else to consider.

    The 5.68 lbs of additional CO2 generated during sleep mode times millions of Macs out there seems to be a somewhat significant factor for those concerned about climate change.

    • On the flip side, the power bump when turning on a Mac – or any electrical device – stresses the internal components (chips, caps, etc.). That can possibly lead to early component failure. The temperature change from power cycling contributes also. It comes down to what you are most comfortable with. I’m a shut down when not using person, btw.

  • Nice article. So what shall I do with my Mac Mini M1? Just put in to sleep every night instead of shutdown? Just to be sure Thanks.

  • I definitely prefer to put my 2019 iMac to sleep at night as I like to pick up exactly where I felt off at the end of the day.

    My big question is… should the fans continue to run while in sleep mode? Power nap wake for network access as unchecked, and yet my fan continues to run all night on sleep. It is a low rpm for sure, but is that right?

    My support specialist thinks all new iMacs need the fan running even in sleep mode… doesn’t seem right.

  • My wife’s 2015 Mac Air running Catalina does not like power nap enabled. The result is that her mac heats up so very much that it’s uncomfortable to the touch. I unchecked the power nap box and her computer has returned to its normal temperature.

    Additionally, my mac mini 2012 running Mojave does not like power nap enabled either, so I unchecked that box as well.

  • These small savings don’t look significant until you add them to the savings of other people. 5.7 kWh saved annually is not much, but multiply that by a million Mac users.

  • What about power? Should we leave it always plugged in then? And if yes, what will that do to the battery?

  • The best environmental solution would be to put the lead back into the solder used on motherboards.

    Without lead, the solder is not ductile enough to handle vibration and heat/cold cycles — so solder cracks, the board fails, and the computer gets trashed since that is cheaper than the labor cost for repair.

    AFAIK the Government & military still special order computers with lead solder for critical functions.

    • I always use a OWC TB3 dock and power my 2016 MBPro with it. Will I damage the computer batteries by always having the “AC-adapter” on so that the battery is always charging?

    • I have two Thunderbay 3 units that drop their connection if the drives go to sleep.

      The OWC suggested solution was never to put the drives to sleep. Has this been fixed?

      I would really like to use powernap!

  • I am running a Mac Mini 7,1 with Mojave 10.14.6.
    No sleep settings.
    When I do want to leave it on over night and simply turn off the monitors, some time ago it began rebooting at midnight.

    Preferences > Energy Saver is set:
    Never turn display off
    Prevent computer from sleeping when display is off.
    Wake for network access.
    Startup auto after a power failure.

    The Schedule option does not have a Start up or Sleep option selected.

    However – the box forStart up or wake is “hot.” White, with firm outline for box. There is a time set for 12:00 AM.

    The Sleep/Restart/Shutdown box is not “selected.” It is grey, and the 3-option menu is greyed out.

    The default time for both is 12:00 AM. Although neither box is checked, the Mac restarts every night at Midnight.

    Unlike older Energy options, there is no “Off” or blank space to select nothing for time.

    So that I can do some of the overnight tasks, I have set the “Start up or wake” box for Friday at 3:00 AM. So far, the only way to keep this machine from rebooting is to select an arbitrary time for Sleep/wake.

    This is not the case when I run Catalina on other partition.

    Anyone?

  • My Mac Mini is set to never sleep, so I don’t see the benefit of a “Power Nap”

    My Mini has disks that have my movie archives that my Apple TV uses.

    If my wife can’t sleep and the Apple TV doesn’t respond, I get woken up too! “If the wife ain’t happy, nobody is happy!”

  • I’ve been using Macs (MacBook Pro and now an iMac) for maybe 15 years or so (my memory is not so great as I age). However, I’ve literally NEVER had a kernel panic in all those years. I keep reading comments about sleep problems and kernel panics, and I really can’t understand how I can somehow be “immune” from these things? If I ever got a kernel panic, I would get a fix for it, since this is NOT normal at all, in my experience. How people can just “live with it” (a kernel panic) is beyond me.

    Maybe since I’ve never used Windows in my life (going from IBM mainframe, to SGI Unix, to Linux, and then to OS X/Unix), I’ve never had these problems on an on-going basis, and therefore have never just “lived with them”. But, since I have never used Windows, I can’t really say that it’s ever been unreliable, but that’s the one assumed difference in my past experience.

    I have only used OWC external disks and memory :-), but I can’t believe that it’s the ONLY reliable producer of peripherals. I did have a bad “rotating” disk at one point, but replacing it solved that. I’ve also tried to always (when they became affordable) use SSD drives internally, at least for my system disk.

    And, of course, I feel obligated to swear the required: “I have NO relationship to Apple or OWC. And, sorry for the long comment (and I still really do text “in complete sentences”, quoting from some commercial I believe ;-).

  • Great information! I have always wondered about this topic. You explain everything in a clear manner. I will now just put my iMac to sleep at night.

    Thanks….

  • What about the added risk of interference with the Mac’s system, such as adding spyware, ransomware, etc during the hours when the user is inattentive?

  • If you are worried about your Mac contributing to climate change my suggestion is to take your mac to a recycling center, sell your car along with all you other possessions and move to the woods. You still won’t make a scintilla of difference to the climate but at least you will feel good about yourself. :)

  • Hi Apple,
    Please I a solution for this problem, I put my iMac 27inch mid 2011 to sleep for several hours but my computer shutdown itself. I tried all possible means to start the computer but will not start. No power at all. Please how best can you help me?

    Thank you

  • So just dropped off my Late 2016 MBP 15 @ the Apple store to have the logic board replaced to the tune of $800… According to the Genius staff there, the fact that I only rebooted/shutdown the machine during OSX updates (as opposed to shutting the lid and going into sleep/power nap) contributed to the failure of the logic board and was considered “abuse” of the device.

    My 10-year old Lenovo ThinkPad has never had a single board failure and was treated the same way the first 5 years I had it… As were two Samsung Satellites I’ve owned since… Jus’ sayin’.

    • Really?
      My 2010 MBP gets treated the same way and still runs fine so maybe you just suffer from electronics can and will fail at some point scenario. An HP laptop I had purchased about 4 years ago, and still running Windows 7 failed in 3 years, and just 2 weeks after I bought a new power supply to charge the batteries because it failed as well. I have such great luck with my MacBook , I now dual boot it, so that I can run Windows on it.

  • Now I know why when I am traveling and I leave my car and come back my mac book is smoking hot if I don’t shut it off. And when I am at home to a lesser extent it overheats when the lid is shut and it should be sleeping cause I always have the thermostat set in the low 80’s and it runs hot when the temperature is that high. And sometimes when I open it in the morning the battery power is down to 40%. Or sometimes when I am traveling the battery drains really quickly. About the only thing I would want my mac to do in power nap is index. I can live without that though. I turned power nap off for both powered and battery mode and it’s never going back on. Thanks!

  • This seems to conflate display sleep (just turning off the display) with Mac system sleep, which are different things. Power Nap is interesting since it will happen during system sleep (which is like when a notebook Mac closes its lid).

    • As someone mentioned earlier, Power Nap can now be found in “Battery”. I hunted all over the place for “Energy Saver” before I found Power Nap in Battery. Makes you wonder just how accurate and up-to-date this article is.

      • It mentions in the Energy Saver image caption that it’s found in the “Battery Pane in Big Sur.” As several have missed this, we’ll make mention of it again elsewhere.

  • With my 2008 Mac Pro and OS 10.11.6, I was finding that my available space was decreasing 5GB to 10GB if I didn’t restart periodically. Some operations were slowed. With the 2018 Mac mini, I have found that after a week or more, the loss of storage space was down maybe 3GB to 5GB. An improvement with Mojave over El Capitan.

  • I’ve found it more beneficial, both for me and my iMac 27″ 5K to simply shut down for the night. Why? Because about 30% of the time in plain Sleep mode, it crashes and restarts during the night. The rest of the night, it usually wakes up about every 70 minutes or so for about 45 seconds, then goes back to sleep, which activates all my external drives and makes too much noise, interrupting my own Sleep. I have NO need for the “Power Nap” and would say that most people really don’t need that feature. Just chill and power off. Ah, quiet and calm.

  • I Never heard of Power Nap before. I was happy to find out that both my computers are using Power Nap. Your article is clear and thorough. Thank You very much .

  • There’s another good reason to put your Mac to sleep instead of switching it off. The physical stress on various components due to thermal cycling between active and off states is reduced if the computer never really gets as cold as it does when it’s switched off. So, sleep adds life to the computer.

      • I think I’m on my fourth 17″ MBP due to the bad chip design. 17″ is the perfect size for your only computer. There are people who will remove the chip and even replace it, if the failure has not yet fried the whole board. But the labor cost of taking apart the computer to expose the chip is very high.

  • I cannot understand how anybody can possibly leave their (modern) Mac running for months… Unless you are either not using it or you are running an older OS. Ever since I switched to 10.13 (when it was released) the kernel crashes hard at least twice a month… Sometimes within just a few days of the last crash.

  • i always shut mine down at days end, i don’t mind waiting 2 extra seconds for email to load, or for the
    small amount of time needed for updates.

  • Great Article. I am “upgrading” from a 2009.5 MBP laptop to a 2019 21.5 iMac.

    Glad to get all of these tips.
    Have a great day from Sun City West, AZ
    73
    DavidCee

  • Great article! It answers a lot of important questions. Mac should include a manual that answers questions like these with every computer they sell.

  • Thanks for posting this. Nevertheless I will continue to power my various portables and iMacs down rather than let them sleep, for the following reasons:
    (1) at this point in time, any reduction in energy use should be encouraged and applauded. As an example, think about the additional CO2 if a million users follow your advice, that’s at least another 5,000,000 pounds of CO2 for literally no good reason. I urge to to avoid the idea that energy use is “trivial”. Nothing is trivial with 7.5+ billion humans on the planet.
    (2) It’s been my experience that many macs have problems waking from sleep. It’s far safer to shut it down than to have it freeze and refuse to wake.
    (3) There’s no reason users can’t get in the habit of doing their own maintenance, as programs like Onyx are quite easy to use.

  • I purchased my 27″iMac in 2011. I checked, I do not have the Power Nap. I have always let my Mac sleep. I only shut down a couple times a week for a re-start. What suggestions do you have for me?

  • This is true and has been my practice for years. However, it is a good idea to shut down and then restart your Mac about every 3 weeks to clean out memory cache(s) and reset other little things.

    • In my case, I’m using enough concurrent memory-intensive apps at times that a utility like Clean My Mac comes in handy for freeing up RAM during the day and on demand. I always leave mine in sleep mode at night so a backup can run without impacting daytime usage.

  • What about attached drives during sleep. What happens when a firewire dirive is “unplugged” while MacBook Pro asleep. Is it at risk of corrupted data?
    Put computer to sleep 9PM. at 6AM unplug attached drives and external monitor to take computer to work.
    Advice please

  • My history suggests that “Sleep Mode” ejects external drives (improperly). Does the Power Nap take this into consideration?

    • What Mac are you using?
      With my Mac Pro and with the external drives connected through the eSata, I was having that problem – it just could not maintain the connection.

      With my Mac mini (2018), I had the same problem when the external drives were plugged into a USB 3.0 hub. I would wake the Mac mini to find multiple notifications that my disks had been improperly ejected. Evidently, the 10-port hub does not maintain a connection 100% of the time. The hub also kept dropping the Logitech mouse when the receiver was plugged in there. Now it is in the USB port of my wired keyboard. No more mouse problems.
      The external drives are now connected through the USB hub (Anker) plugged into one of the Thunderbolt ports of the Mac mini.

  • If the Mac is sleeping at night, it’s not likely producing any extra CO2 usage. Power plants are running all night, whether you use that minuscule amount or not.

  • Thanks for this post, Steve.

    I’m interested in how you think connected hard drives affect this strategy.

    What’s always kept me from using sleep (vs shutting down) are my connected drives, which keep running even if my iMac is power napping. So while my CPU is only using a sliver more energy than vs shut down, my drives are still using power, tilting the balance well in favor of shutting down. Plus, since drives only have so many hours of use, logging 8 or more additional hours overnight.

    Still, would you still Power Nap vs shut down in my case?

    • You can have the hard disks sleep – System Preferences > Energy Saver > Put hard disks to sleep when possible

  • My 2018 27″ Retina iMac frequently shuts itself down with a kernel panic (overnight) when I stay logged in but sleeping. I did not have “Power Nap” enabled, so I will try that.

  • There’s an error in your last calculation.

    Assuming your estimate of 5.68 lbs of CO2/5.7 kWh of electricity is correct, then 5.7 kWh is the equivalent of driving about 6.4 miles in a car getting 22 mpg.

  • My problem is that sometimes, when I put my MAC to sleep, it doesn’t wake up. The screen is blank when I open up the MAC. It is not due to a lack of battery power either. Otherwise, the keys may light up, or the screen should show up, but even after at least 5 minutes, I can’t get the keyboard to respond.

    • “My problem is that sometimes, when I put my MAC to sleep, it doesn’t wake up”.

      What Mac model and macOS version? It could be a defective GPU.

      • I’ve got a similar problem with my late 2015 iMac running 10.14.3. If I manually put it to sleep it sometimes fails to wake up in the morning via BT keyboard or trackpad.

        After reading this I did turn on Power Nap. We shall see if that helps or not.

        • Pavel, Jazz1 – I had the same issue (screen not waking up) with my last iMac. After a while with Apple support a reset of SMC and PRAM (or NVRAM… can’t remember) fixed this.

        • My Mac mini (2018) has OS 10.14.3. It replaced a 2008 Mac Pro because Apple didn’t produce the new Mac Pro and I didn’t want to buy a ‘new’ one with 5-year-old electronics.
          I thought it was not waking from sleep. I usually tap the mouse button to wake it. If that does not wake it in 5-7 seconds, I tap the return key (wired keyboard). If that does not work, I tap the key I have programmed to take a screen shot. Then I hear the chime that tells me it took a screen shot, so I know it is the display not waking. I unplug the USB-C plug behind the Mac mini and re-insert it. The display is ON.
          Something is preventing the Mac mini Thunderbolt port from sending the signal to the display (23″ Apple Cinema Display). It has occurred 4 times in the 3 months I have had this Mac mini.

          If you have an iMac, then you probably don’t have a connection problem, but you never know.

          • I’m getting in late on your 3/15/2019 comments about your 2018 Mini not connecting to the display when it wakes up. I have the same problem with my 2018 Mini when I power up (not wake up), but my monitor (a 2018 Dell) is connected via the HDMI 2.0 port, not USB3. To recover video capability most times I have to hold the start button on the Mini to shut down, then I restart. That may be necessary several times. If that doesn’t work, I unplug the Mini, 15 seconds, replug, wait 5 seconds, and restart holding down the Left Shift Key (ie., reset the SMC). If that doesn’t work, the final step is to quit, unplug as above, then restart holding down the Option, Command, P, and R keys (ie., reset the NVRAM/PRAM) until I hear the “Chime.” At some point in that series I’ve always been able to recover video –– so far; but it’s a pain.

        • I have the same problem. I had ask it to never sleep. Says it shortens life of monitor ? My Mac mini shuts down when I let it go to sleep. Need to turn it on with the power switch ?

    • There’s been a long-standing “complaint” out there about the screen saver locking up. I’ve got one of the early Mac Pro and suffered from this – sometimes the screen saver would lock after a couple of hours, necessitating a reboot – very irritating. I’ve taken to logging out, leaving myself at the login screen but with box still running.

  • Sure; Recently read article sayings OWC had a turnkey program to upgrade “vintage” iMac to “better than new…”. Can my late 2009 (10.1) 3.06, 21.5in w/8gb ram, 500,gb SSD be any further upgraded? If sox cost?
    Appreciate any info.
    Lloyd Stevenson

  • Thank you for the facts on this issue. Of course the other question is how much, if any, wear and tear shutting down and starting up a Mac every day causes compared to sleeping it every night.

  • I don’t find Power Nap option using Apple Menu, system preferences, Energy Saver and using Mojave 10.14.3 . Where did it go?

    • Do you see all the other options?
      •_Prevent computer from sleeping automatically …
      •_Put hard disks to sleep when possible
      •_Wake for network access
      •_Start up automatically after power failure

      And does it have the statement “While sleeping, your Mac can back up using Time Machine and …”?

      If the Enable Power Nap is the only item missing, maybe you can try the Restore Defaults.

    • My desktop Mac has racked up 1,550,000 BOINC credits helping out a variety of compute-intensive projects over the years — while I’m asleep or away from my desktop. Does this create more wear and tear on my desktop than simple being asleep?

      • I configure my mac to let the display sleep but never the processor. Drives will usually spin down on their own due to lack of activity.

        I’ve been running WCG since 2004, before it moved to BOINC. I’ve used Win pcs and now Mac Minis. Almost always running 24×7. In all that time I haven’t had any hardware problems caused by such work (that I know of). I am concerned about running a continuous heavy resource load on macs so I usually limit the cpu load to +/- 20% to prevent over heating.

        If anyone really wants to stress test a computer try running GIMPS aka PRIME95. :-)