Written by: hexley on Sunday January 06th 2008, 12:50 PM
Filed under: Hardware
Since the introduction of Macintosh hardware, there have been several ways to turn your computer on and off. In the old days there were real mechanical switches. Today’s modern hardware has illuminated, touch-sensitive power buttons that at times can confuse new users. Especially those coming from a non-Macintosh environment.
The easy part… turning your computer on.
If everything is hooked up correct, press the power button once. You will hear what is collectively known as the “startup bong” or “startup tone”. While this button has been placed in some less than ideal locations on certain Macintosh models, most people figure out how to turn on their computer with little hassle.
The harder part…turning off your computer.
A logical person would think pressing the power button once more would turn the computer off. This is not always the case. There are two things this button can do. First is turn off your computer, the other is restart it. You can further bypass the button entirely and use your mouse to tell the computer to restart, shut down, or even sleep.
Let’s go through all the options.
Software based restart, shut down, and sleep.
If you move your mouse to the upper left corner of the screen to the apple logo, click and hold, or click once and release, you will see three options. Sleep, Restart, and Shut Down. Selecting “sleep” will put your computer to sleep.
Sleep means your computer is on, but in a very low power mode. Your hard drives will “spin down”, meaning they are drawing very little power. Your open applications and unsaved data will be relatively safe, waiting for your return. Depending on your model and configuration, you wake your computer my moving the mouse, clicking the mouse, pressing a keystroke, or pressing the power button.
You can always tell if your computer is asleep, as the power button will have a gentle pulsing light glow to it.
Shut down will remove power to your computer. You can safely chose this option at any point in time. You need not worry about unsaved data, as you will be prompted to save your data in any open applications.
Restart is just like shut down, with the exception that the computer will automatically boot back up again. Restart will run through all the same steps that shut down does, with the only difference being the computer comes back to a clean state. This can be a great first troubleshooting step if something is misbehaving.
Hardware based power control
You can also control these options with the actual power button. Pressing it once will pop up a dialogue on your screen where you can select to restart, sleep, shutdown, or cancel the operation. These methods will behave in the exact same ways as mentioned above.
Your power button can do one thing you can not do any other way. The power button, when held down for more than five seconds, is a somewhat more graceful method of yanking the power cord out of the back of your computer.
As much as we would like to think computers never get stuck, at times, they can get cranky. Poorly written software can take your computer down, lock it up to the point where you can not do anything. At other times, failing hardware inside your computer can wreak havoc on its performance.
About the last thing you want to do is abruptly rip the power chord out of your computer. Simply hold the power button down for a few seconds, and it will shut your computer down. Sounds harsh, but at times, it can be necessary.
I would say more than 3/4 of the tech support calls I take the customer states they pulled the power plug. Given this, I have to assume not too many new users know about holding the power button for a few seconds.
At any rate, it sure beats crawling around under your desk, or digging around the back of your computer.
A final note, if you are a laptop user. Simply closing the display of your laptop will drop it into sleep mode. Laptops take special efforts to manage power as efficiently as possible, so there are a few different types of sleep your laptop can go into. At this time, just know, it is more than safe to simply close the lid on your laptop.
I’ve lost my Mac start-up tone and zapping the PRAM doesn’t work. Suggestions?Comment by Mike 01.07.08 @ 9:50 AM
Interesting, If you have external speakers, try unplugging those. I would like to rule out it being an issue with your computer, or your speakers.
I assume your computer can make other sounds?
You did not happen to install some 3rd party tool to change the start up tone volume level?Comment by Scott Haneda 01.07.08 @ 9:58 AM
Nope, everything else works fine and there is no 3rd-party stuff involved. This is a known Mac problem (others have it and posted numerous suggestions on other help sites, but none of the proposed fixes worked for me. I’m just amazed that Apple is simply ignoring this problem!! One good thing, however, is that it does not appear to have any adverse effect on anything else. MikeComment by Mike 01.07.08 @ 12:27 PM
If you have a spare moment, I would love a link to some data on others having this issue so I can research it further.Comment by Scott Haneda 01.07.08 @ 7:16 PM
Sorry, but the other people with this problem (IDs only) were on another help forum several months ago, so I really have no way to direct you to those; I wish I could. /MikeComment by Mike 01.08.08 @ 1:27 PM
May I suggest a clarification. When you “… move your mouse to the upper left corner…” you should be aiming for the Apple logo. If I was a new user, I might interpret the instructions to mean anywhere in the vicinity of the upper left corner. I’m looking forward to reading the rest of the OS X Help, and learning a few tips. Hope you don’t mind the occasional suggestion.
Thank for putting this together. If I’ve posted this in the wrong area, please let me know.
SethComment by Seth 02.02.08 @ 9:10 AM
Thanks for the comment, we appreciate the feedback, you suggestion is a good one, and we will make a small editing change.
Ah, this is good to know!!! As a Windows switcher I have pulled the plug out from behind my iMac when it froze. I had no clue what to do since the Ctrl-Alt-Del doesn’t work on Mac. So I unplugged it. (It’s using the Second Life software that freezes it. I will most likely be uninstalling it.)
A light press of the power button puts it to sleep. I like that feature. Now I know to hold it longer to shut it down.
Also, I was using Word from MacOffice2004 and it froze in the middle of selecting a font. I waited and waited to no avail. So I experimented and held down the ESC key to see what would happen. It terminated Word. I’m hoping that was the correct thing to do. I opened Word back up and everything went smoothly after that.Comment by Donna 02.08.08 @ 1:06 PM
You might mention that holding Command-Ctrl-and hitting the power button will perform the same function as Ctrl-Alt-Del on a PC.Comment by Josh 02.08.08 @ 3:17 PM
I have tried your method on 2 Macs that I have access to now. All it does for me is put the machine to sleep. I have found that some of these methods only work on specific hardware. This is why we try to keep the tutorials focused on things that work across the board.
There was a time many years ago where you could use your keyboard to start up your computer, and you could hit a 4 key combo and force an immediate reboot.
Those days are gone with USB taking over. Thanks for posting your comment, it could be handy for those who have the correct hardware combination.Comment by Scott Haneda 02.08.08 @ 4:30 PM
Command-Control-Eject works across the board as a shortcut to restart. Control-Eject will bring up the Shut Down menu, and Control-Option-Command-Eject will Shut Down. If your keyboard doesn’t have Eject, F12 will work.
One annoying thing with leopard I’ve found is that if you are running time machine and put it in “sleep” that time machine will wake up mac…is there a fix for this~I’ve not found any options other than shutting off time machine before sleep mode…then remembering to turn it back on.Comment by JimB 02.14.08 @ 2:30 PM
@JimB, power management is very strange on every Apple product out there. I have a laptop, and a desktop, and both behave different in how they sleep and what can wake them up.
I personally have not had Time Machine wake a machine up, and had to take steps to keep the machine awake at times to get a full backup.
I would suggest you try telling your machine to “Put the hard drive to sleep when possible” in the Energy Saver prefs. Generally, a spun down drive is pretty hard to have spun back up again unless you wake the machine up.
Rather than shutting off time machine, which you may forget to turn back on, you could unmount your second backup drive, that would make time machine ignore it as well.Comment by Scott Haneda 02.15.08 @ 6:11 AM
I’ve noticed on my eMac (3rd Rev.) that if I have the volume all the way down in the OS, then reboot, I won’t have a startup “bong” but if I have the volume at any setting above zero I will have the startup sound. I’m not sure if this applies in your situation but I just thought it was worth mentioning.Comment by Morgan 02.25.08 @ 4:50 PM
I’ve been wondering whether I should be turning my iMac (desktop) off when I’m done with it or putting it to sleep? The manual says to leave it in sleep if using it every few days (which I use almost daily since it wakes up so quickly) but I’m just wondering if that’s ok for the machine?Comment by akc 03.20.08 @ 2:31 PM
@akc, there are two schools of thought on this one. I generally leave my machine on all the time, and just let it sleep.
OS X has a few maintenance routines that run on a schedule. If you always shut your machine down, those may not get a chance to run.
On the other hand, sometimes, a clean restart will make your computer work better, as over time it can have applications clog up memory and do other bad things.
In general, it is up to you, you are not going to hurt anything by leaving it running, or shutting it down.Comment by Scott Haneda 03.20.08 @ 5:01 PM
After my MAC has been asleep, when I move the mouse it has in the past brought up the active screen. Now, after sleep move, the page that is brought up in the basic start page requiring passwords to open up the computer and additional passwords to send or receive e-mails, etc. Why is it requiring that I go through the basic intro set up contrasting with the simple “awakening” in the past?Comment by richard baughman 07.26.08 @ 8:39 AM
I have an IMAC G5 with current Leopard. Recently my computer has been refusing to wake up from sleep mode. When I approach the computer which is in sleep mode I can see the white light slowly flashing on and off. I click the keyboard and/or the mouse as usual to wake it up and the light will stop flashing and it simply wont wake up.
I have no external HD or Speakers just the printer and scanner. 8 out of ten times it will not wake and I usually have to resort to turning the power off at surge protector. Ideas?
@bruce, first I would try and unplug the printer/scanner and see if the issue goes away, then you have a point to start looking. If that does not work, create a new account, login to that account, and see if the problem happens in the new test account. Also, in /Applications/Utilities is a Application called Console, if you open that, it allows you to look at logs. Click on ‘All Messages’ and see what you can see that may be related to sleep, or Power Management. You should notice there is a time stamp, so take not of the time just before you were forced to reboot.Comment by Scott Haneda 11.14.08 @ 11:04 PM
@akc I use a 24 inch iMac with Apple’s wireless mouse and keyboard. (bought 1st of July 2009) and have it powered through a Watts Up? power meter. To preserve battery life: I turn the keyboard off then click on “Sleep” the power drops from about 75 watts to 1.5 watts. When I turn the keyboard back on everything is where I left it. I see no reason to turn it off or Restart unless new software requires it.
Incidentally, a Mac mine even consumes less power in sleep, there is no monitor. As near as I can measure it is about 0.1 watts.
It is kinda fun to know how long a Mac desktop has been on.
If you go to “Terminal” and enter: “uptime” (without the ” s and press return, it will tell you how long it has been on. My mini was on over 63 days. Both were Shut Down to install Snow Leopard.
Why does our I-MAC turn on by it’s self during the night? We put it to sleep but it pops on with out a mouse touch or keyboard touch. Is their a virus etc. in the system?? I’m a new MAC user so should I actually shut the system down rather than use the sleep mode at night?
Regards, David BurrellComment by David Burrell 01.22.10 @ 8:10 AM
Recently I have been unable to start my Imac g5 (using OS 10.5.8) by pushing the power button. I can only start the computer if I turn off & on the power at the surge protector and then trying the power button. Any ideas why?Comment by Bil 01.22.10 @ 8:17 AM
Can you remove the surge protector so we can test and rule that out as source of the problem? Plug the computer directly into any wall outlet and see if the problem goes away.
You may also want to take a look at our post titled The importance of an uninterruptible power supplyComment by Scott Haneda 01.22.10 @ 5:52 PM
You can shut down the computer if you want. I tend not to, and wile I have never found any hard facts to back up my logic… I have never had a light bulb just burn out, it is always when you turn on the switch and it gets that initial burst of power.
I have long thought computers were analogous. I know there are prevention circuits inside them to protect against surges, I still lean on using sleep rather than power down method.
As to why it would magically turn on, a few things could be the culprit.
First, you need to make sure it is sleeping, it could just be that the monitor has gone to sleep (black screen), but the machine itself is not really asleep. Applications like Entourage are known for preventing a machine from going to sleep if you allow it to check email on a schedule. Any application that does background work can prevent or interfere with sleep.
One workaround and a much more secure way to deal with computers in general, especially laptops, is to set the Security Settings in the System Preferences to “Log out after x minutes of inactivity”. This will gracefully close any and all apps you have running, and take you to the login screen. Your sleep settings will still hold true while at the login screen.
The solution to your issues, assuming you are in fact really sleeping, which you can chose from the Apple Menu and selecting “Sleep”, will be in the Energy Saver Preferences.
Open the System Preferences from the Apple Menu -> System Preferences -> Energy Saver. Make sure that “Wake for Ethernet network access” is not checked. This is used for a feature called “Wake on Demand“, which is very handy in and of itself, but could explain your problems.
If you want this feature on, which many do, you will have to unplug all your 3rd party peripherals such as printers, and add them in one at a time, until you find the device that is kicking your machine into a woken state.
There is a little more data about Wake for Network Administrator Access (Ethernet Only, Wifi does not seem to apply), and Apple also has About Energy Saver sleep and idle modes in Mac OS X.
I would also take off the “Start up automatically after a power failure”, that setting largely being good for servers. Or if you have converted/use your Mac as a movie viewing device connected to your TV and desire it always on.
Also check out the schedule options (also in Energy Saver Preferences), which could be automatically shutting down and then rebooting your machine on some schedule.
Finally, the last thing it could be would be corrupt Power Management Settings (PMU). To reset the PMU, which every mac does it a little different; some require you to open them and press a button; usually the older G4′s are set this way. The PMU controls everything from the sleep, wake, fans, and a lot more. It can get messed up at times.
It also looks like Apple has moved from a PMU to a SMU, or System Management Controller on some systems. You can look at instructions for resetting the SMU on your imac as well.
Oh, one last thing. Many of these settings are stored within internal memory of the computer, but need power in order to maintain the remembering of those settings. This is done with a small battery inside the machine. While most of these batteries last the lifetime of the machine, and often longer, at times, they can go bad or corrode, causing all sorts of erratic behavior.
If you find a corroded battery perhaps due to living in a humid or beach front locale (salty air is a killer), do your best to clean the corrosion off. Radio Shack will sell a circuit board cleaner that is safe for getting on any electronic components. This product comes in a red spray bottle last I looked, and is highly alcohol based, so it can evaporate quickly.
Battery replacement can go a little beyond what the casual user may be interested in performing, I would try the other suggestions first. Some machines need Torx style screwdrivers, which not everyone has on hand.
Here is a pdf from Apple that shows how to do battery replacement on one iMac, though you will have to google for your specific model. Granted, just opening up the iMac, it will be pretty obvious as to where the battery is located at. Replace it, or meter it to make sure it has the marked voltage. Make sure you take note as to the orientation of the battery, it is not always clear, and the markings on the circuit board can sometimes be hard to see. You definitely do not want to put it in backwards.
Most Macs use a 3.6 volt lithium battery
As a final step, reset the PRAM as well, which can often times help clear out any goofy settings that have built up, or become corrupted.
Please come back and let us know what you found out.Comment by Scott Haneda 01.22.10 @ 6:39 PM
I have another (unknown?) thing about the power-button. Ran into this when trying to bring my iMac G5 back to life.
If you keep holding the power-button while powering up (for about 10 seconds) the iMac (G5) will generate some sort of loud testtone.
I have no idea what this does and I also don’t know if this is “normal” behaviour or just happens on my machine because it is completely dead. Couldn’t find anything about it anywhere online. In fact; I ran into this article because I was searching for an explanation about this “test-tone”.
Anyone has any idea what this is about? It doesn’t seem to do anything besides making noise (sounds like a television testscreen tone) and my iMac is still very very dead.Comment by Ruben.cc 08.05.10 @ 5:45 AM
Hi @Ruben, while this is somewhat different depending on the hardware you perform the “button hold” on, on the G5 you are performing it on, it has one function. That being to put the machine into firmware update mode.
It will not harm anything to press the button if your firmware is up to date or not. As long as you do not have the firmware update software opened on your computer, no action will take place.
You can read more about the specifics of firmware updates for the G5 here. Information for firmware updates for all models of Apple Computers can be researched here.Comment by Scott Haneda 08.05.10 @ 10:01 AM
Thanks for the reply Scott! Guess it’s pretty useless for my situation then. Found out that my “problem” has to do with defective capacitors. I’ll have to dig up the old soldering iron and replace 16 blown up ones.Comment by Ruben.cc 08.05.10 @ 11:18 AM
@Ruben, yep, those imacs are known for that. It is a pretty simple fix, go to your local electronics store and get a good quality cap. Popping out the old ones and putting in the new ones is really simple. The are large, no SMT stuff here, any high school kid should be able to handle it. Since you have past soldering experience, I would not suspect it to be a problem.Comment by Scott Haneda 08.05.10 @ 11:27 AM
can anyone tell me how to change the function of my power button on a macbook, it keeps turning itself off and apparently if i change the function so that it does nothing this will stop it however i do not know how to do it?Comment by Debbie 12.08.11 @ 11:17 AM
@Debbie, what is causing the button to be pressed? Just pressing the button will not turn off your computer, it will bring up a dialog box asking if you restart, sleep, cancel, or shutdown.
I am not aware that there is any way to change that function of the power button. You can set the power button to sleep through the command line but that is an advanced feature and I would not recommend it.Comment by Scott Haneda 12.08.11 @ 4:47 PM