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I typically drive less-than-20-minute of local roads between my home and office, during which I usually keep my Macbook Pro closed but powered on and in a backpack in back seat. Is it harmful to its hardware? If so, how and how much harmful?

I am trying to decide if it's worthwhile to take a few minutes to power it off properly daily before leaving office or doing it is virtually meaningless.

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2 Answers 2

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Short answer: No, it's fine, don't spend another mental cycle on this.

.... and now, a long, rambling answer...

Do I need to power off my Macbook Pro during commute between home and office? Either approach is fine. Obviously being suspended will consume battery power slowly (very very slowly). If you're going to run on battery for a while at home too, then the power cost of shutting down and booting up may end up being more than being suspended.

Is it harmful to its hardware? If so, how and how much harmful? Apple encourages people to use their machines like that. It could only be harmful if the machine is being woken up (and thus spins up the hard drive while the machine is being vibrated hard). Anything that would generally damage the machine in a suspended-state would also damage it in an off-state. Unless you're doing something really weird, it's not harmful.

I am trying to decide if it's worthwhile to take a few minutes to power it off properly daily before leaving office or doing it is virtually meaningless. I think it's a serious waste of your time to power-off. I think it also provides unnecessary (though trivial) wear-and-tear on your hard drive.

Ultimately, the practical difference is so superficial that you may as well just do whatever you 'feel' is best. If you're in constant fear of zombie apocalypses (like me), then you may be happy to know that your laptop in its powered-off state may end up having enough juice left in it, that when some survivor takes it from your corpse, they may manage to use it enough to solve some key problem and save humanity.. All because you left the machine in a state that left the battery charged. Not that you'd ever get props for it. If you're like me, however, you'll just suspend the machine and let the rest of the human race fall with you.

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this depends though too, the only piece of hardware i would worry about is the Hard drive. If it's an SSD, then no problem, but if it's a platter and if you hit a large bump or something along the way and the computer decides to do something in the background, it could corrupt some data. Also, overheating is a possibility if leaving it in a backpack while it's on. I think putting it to sleep would help though. –  Matt Sep 22 '11 at 5:56
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@Matt: if the computer is suspended, then the hard disk is certainly powered down and its heads are parked. –  Joachim Sauer Sep 22 '11 at 6:32
    
@JoachimSauer except that the OP never said anything about suspending their MacBook, that was (probably incorrect) assumption that Doc made. In fact, the OP specifically asked about leaving their MacBook powered on. –  Synetech Jan 15 at 20:58
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To most people Closed = Suspended. You close the lid on a Macbook and the default operation is for it to suspend. By powered on, he is obviously talking about the opposite of taking the time to turn it off fully. –  Michael Frank Jan 16 at 4:44
    
@Synetech the OP said they close their macbook, by default that means the machine's suspended. –  Doc Sep 16 at 22:17

If you are not using something like 'Caffiene', or some other 3rd-party tool to keep the MBP (Macbook Pro) actively running while it is closed, your MBP should enter stand-by within a minute or so, when the lid is closed to put into your backpack.

If the MBP is in 'stand-by', the HDD will not be spinning and is therefore very safe to transport. However, some software may, intentionally or unintentionally, keep your MBP from entering stand-by mode. If that happens, though, all hope is still not lost.

Looking at the specs for a typical 2.5", internal HDD these days yields the following:

Environmental (operating)     Shock (half-sine wave) 400 G/2ms, 225 G/1ms
Environmental (non-operating) Shock (half-sine wave) 1000 G/1ms

The first thing to notice is that the limit is lower for a shorter impulse. This suggests that the drive is more sensitive to a sharp physical shock of short duration than to mild acceleration (typically < 1 G) as may be experienced on your daily commute.

If your backpack provides any padding, and you are careful to place your backpack on your floor, where it can't slide off the seat and hit the floor, it should be fine even if it is still running. But, if you are walking out and smack your backpack into a wall or doorframe on your way, the risk is much higher.

Even at the higher risk, though, the real risk is pretty low. Imagine the impact necessary to damage the drive while it is off. The shock it would take to damage it while running is still greater than 20% of the non-operating shock tolerance. That is a pretty significant shock.

For the record, I never power-off my MBP, but it DOES go into stand-by before I bag it.

I hope this helps!

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How do you usually put MBP to standby mode? –  Computist Jan 17 at 18:55
    
@Computist, It's quite difficult to close the lid without it going to sleep / stand-by. On a Windows laptop, you can set the action for the system to take when the lid is closed, but on an Apple laptop, it has never been a configurable option, so far as I know. Depending on what software I have running, it may take up to 60 seconds before it will power-down. You can tell it is sleeping when the fan(s) stop(s) spinning. If I wish to manually put it into sleep, I just press the power button and it asks me what I want to do: restart, sleep, cancel or shutdown. –  MrWonderful Jan 17 at 20:05
    
With 10.9, pressing power button directly blacks out the screen -- perhaps that's "sleep"? –  Computist Jan 31 at 0:07
    
@Computist I would expect the MBP to go into 'sleep' when the lid is closed. The power button, if pressed quickly, will also toggle between 'sleep' and 'awake.' In order to get the restart, sleep, cancel or shutdown dialog to appear, you must press and hold the power button for 1.5 seconds. See the docs at support.apple.com/kb/HT5869 –  MrWonderful Feb 3 at 8:37

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