PC hardware forum: Fact or fiction? Powering down a PC via the power button will harm it

The newer hardware will gently shut down the O/S and power off the system if the BIOS is set correctly. This ensures that all active apps, processes, etc terminate smoothly, and that any cache and swapfile is cleared. Holding the power button for 5 seconds or so will perform a "dead stop", but if this is done too often can lead to residue from abnormally terminated apps, temp files, or worse - corrupt system files. I have had to rebuild many laptops that have bad batteries and shut down hard while apps are still running.

Hi Michael

The reason why a computer shouldn't be "surprised" with a sudden removal of power is due to the way that files are held open with data cached, ie not fully written to the disk. It's exactly the same situation with thumb drives, which is why you shouldn't unplug them without using the eject or "safely remove" feature.
If the power suddenly goes out, the files are left corrupt or even worse the disc might actually be written at the moment the power is lost.

However!

The power button on modern computers doesn't physically remove power - it sends a signal to the bios, which informs the operating system what to do. The computer then takes the time to close down just as if you'd used the shutdown menu.
You can even configure the button to sleep or suspend, rather than shutdown if you like.
So using the button is perfectly safe.

What you shouldn't do:
Most pc power supplies have a feature for forcing power off - for situations where the pc is crashed and won't shut down. Hold the button in for 4 seconds and power will be removed - this is the same as pulling the plug from the wall.

In summary:
Use the power button if you like, but check how the computer will react in Control Panel, Power, Power buttons.
Don't unplug the power cable or hold in the power button for 4 seconds unless the computer is frozen up.

NB

What does it do to your computer if it is frozen. Every now and then my computer freezes and I have to hold down the power button to restart it. Does that also harm my hard drive?

Hi Droid, that was a simple clear explanation, thank you very much! Thank you Michael for asking the question.

There is no such thing as a "sleep button!" "Sleep" is a function of the POWER button, and controlled by the control panel settings you make under "power." In general, using "sleep" in NOT a good idea. WinXP has had known issues with the "sleep function" being harder to awaken right than a person! "Hibernate" is another function, and should be disabled unless really, really needed.

sorry droid but there IS a major difference between pushing the power button and pulling the plug. after you shut down with the power button and the pc finally shuts down pull the plug. while watching your led lights above your number pad and with the plug STILL pulled try to start your pc with the power button. you WILL see the led lights light up and slowly dim out. this shows that you still had power somewhere in your pc. this power can and does hold on to the problem you started with. this works wonders on most pc screwups.
eg: every once in a while my mouse freezes running windows xp. when this happens if I JUST power off with the power button and then restart my pc the mouse will still be froze up. if i try to power up with the plug unplugged it will drain all the power being stored in my pc. after the led lights go dim i then insert the plug back into the pc. after restarting my pc I no longer have a frozen mouse.
i learned this with windows 95 and then with windows 98. I had a flatbed h.p. scanner that used to lock up with the slightest error on my part. at first I would have to completely uninstall the scanner and my h.p. printer then reload both back in to restore my scanner. what a hassle. after playing around I tried to drain the excess power by unplugging my pc and trying to restart it with plug removed. after the lights dimmed i would replug the cord back into the pc. after powering the pc back up my scanner worked great. this saved me a considerable amount of time by not having to uninstall and reinstall my scanner and printer. many techs will argue this with me but i have seen it work way way too many times.

Droid's last paragraph is very confusing. You wouldn't use the Power button unless the computer is frozen so you would always hold it for 4 seconds. That's been my experience anyway.

my laptop pc is acting weired most times it will not shut down even when it says it is doing so other times it will shut normaly any idea what's going on anybody?? also my task bar icons by clock keep disapeering somtimes there on bootup most times not ????? HELP PLEASE !!!!!!!!! windows xp home circl 2004 average low build this problem only come last six months cannot trace why but not infected with any viruses

When I got this Win 7 PC a few years ago I was surprised to read in setup information to always leave it on. Even so when there are thunder storms or a power outage I have shut it down with the power button. No harm done so far, but I do wonder why should it be on at all times.

Hi, droid,I've had lately crashes and freezing up of my computer and I've used the button so to speak. It was really helpful. Thanks, John

Re: my last response, I just thought of something else.

If you're concerned about what might happen to your PC if & when the power does suddenly die, like in a power cut or a blown fuse, you should buy a UPS (uninterruptible power supply). This is basically a big battery which sits between you and the AC mains, giving you a few minutes of extra power. Enough to shutdown safely and I think they come with drivers to automatically put the PC in a safe state in the event of an issue.
UPS are not too expensive but there is a rolling maintenance cost - the batteries don't last forever.

NB

Fiction. Shutting down the system with a quick press and release of the front power button is safe. Many system cases print a "Suspend" symbol (a circle interrupted with a line at the top, like a watch face at 12 noon) on the front switch, to indicate that it is more of a "power on / shutdown safely" switch than a power switch.

Many of the answers before me got this right. The other posts are simply driven by paranoia and failure to read your question.

The builder probably worked with two or three people who could not be taught to quickly press and release the power button (and many computer users have this very unfortunate condition), and now is telling everyone to shut down via Windows software.

Now I'm really going to throw a spanner in the works. If your system loses power for any reason, or if the system hangs and you have to "5 second press" the button to force a power cut, the risk is small, but the operating system can corrupt leaving you with a system that won't boot normally, and I've had this happen. You do lose the cache data that was in RAM and not written to disk yet. You might hurt the registry, as I've read in the other posts. All these bad things can and might happen. But these are software problems, no physical damage to your system will occur. *** So make proper software backups and be prepared ***. You might kick the power cord and accidentally cut power to your computer (happens to me often). You cannot guarantee 100% uptime on your computer. The best, most reliable computer manufacturers can't, either.

And another spanner in the works. Mechanical or electrical equipment failure is always a risk, even during stable operation of your computer. But most failures occur during power on and off - be it shutdown, hibernate, suspend, or a yanked power cord. Don't be paranoid and leave your computer on forever! Make proper software backups, and the hardware can be replaced, albeit a huge inconvenience. Hard disks have the highest failure rates of any components in the system, so be sure to back up your data. The OS and software can be re-installed, but it is a far greater inconvenience to lose your data.

Always be prepared for hardware and software failure - you cannot avoid it forever, no matter how nicely you shut down your computer.

My two cents.

... my buddy used to have to rebuild his operating system from scratch every time he didn't go through the proper power down sequence. And that isn't always a matter of choice. a system might freeze or power might fail. In those days the computer's power switch was actually a proper mains switch physically cutting the supply power.

Today, after a "hard" power down you will find that there is a disk scan taking place on restart. That is also not there just for fun. There still is a chance of data corruption, to this day.

Now the OP didn't quite make it clear what sort of a system he's talking about, although the bit about "holding the power button down for several seconds" gives us the impression that he is using something with a software-controlled "soft" power button.

In that case, you are right, he is just starting the power down sequence from the OS. And there shouldn't be any harm in that. Since you don't know that just from looking at a PC it is probably good practice to stay away from a power button that isn't clearly labelled "SOFT" - and how many are? And for the same reason i believe it to be a good idea to not teach your customer something that might turn out to be dangerous on some other computer.

Just the other day I actually did something similar to that. I wanted to show my sister something on her new monitor and switched it off for the purpose. That's when I learned that in this case the monitor was the computer and it just unceremoniously switched off. Fortunately, nothing was lost, but there certainly was no warning that this is the computer's power switch, not just the monitor's. I also still have a few machines with a soft power button on the front panel and a proper switch on the back where the actual power supply sits.

So, yes and no. It can be dangerous, still today, but in all cases where you know your metal, you may well be safe. As someone that touches many systems in his daily work I prefer not to jump to conclusions and rather play it safe - I will even double check from now on if I am dealing with a monitor with a built-in computer ...

The OS software over the years have improved. In the earliest version of windows, it was necessary to type "PARK" at the command prompt. By "parking", this stopped the spinning of the hard drive. This protected the Hard Drive.

I my opinion, it is safest to utilize the shut down proceedure incorporated into the OS software.

From my very first Windows days, Win 95 > Win7, I was told by techies never to do a hard shutdown. Its not that it could damage the mobo just that usually a hard shutdown/cold shut down is something you do when your machine has frozen (old BSOD days) and you have no choice and for some reason reset doesn't work. Reason for using the correct shutdown method, from the start menu, is that it tells the hard drive(s) to stop reading/writing save what is in memory and move their read/write arms to the neutral position inside the drive. I believe a hard shutdown would or at least used to drop the arm onto the disc platter thus damaging it. I know tech has come a long way since but I have had many a bad sector on a few hard drives appear after a power out.