USB port drawing too much power?

Discussion in 'Mac Basics and Help' started by poorevan, Sep 13, 2006.

  1. poorevan macrumors newbie

    Sep 13, 2006
    I get this strange message every so often, sometimes more often than other times. It says:

    USB port drawing too much power. The device that is plugged into it will be deactivated.

    There are only two things plugged into the USB-The keyboard and mouse. When I get this message, the mouse freezes. If I jiggle the mouse cable where it is plugged into the USB, it comes back and everything is fine until this message comes up again.

    Ever seen this before? What did you do?

    Thanks for your help.
  2. mad jew Moderator emeritus

    mad jew

    Apr 3, 2004
    Adelaide, Australia
    What brand of mouse and keyboard do you have? If they're not Apple-branded, do you have the latest drivers? :)
  3. Makosuke macrumors 603

    Aug 15, 2001
    The Cool Part of CA, USA
    If jiggling the connector fixes it, that sounds rather like there's a bad wire in the cable, and it's shorting, causing the "too much power" warning.

    Not sure that's what it is, though--if it's just a very poor connection and the power is right at the limit of what it can handle, then when you jiggle it it might be disconnecting and reconnecting, thereby resetting the error until it edges over the line again.

    I wasn't quite clear if the mouse and keyboard are plugged into separate USB ports, or if the mouse is plugged into the keyboard; if it's the latter, you might try plugging the mouse directly into the computer. If it still happens when directly connected, I have to think that there's a hardware problem with either the port or the mouse.

    Oh, if both are directly connected, one other thing you can try is swapping which ports they're plugged into; if you keep getting the error and it's still the mouse that goes out, then it's probably a bad mouse. If you keep getting the error, but this time the keyboard goes out, then it's a bad port with a loose wire internally or something. If it goes away... well, I'm not sure in that case.
  4. 840quadra Moderator


    Staff Member

    Feb 1, 2005
    Twin Cities Minnesota

    I know it says you only have two items connected, but is this happenening when you are plugging in an extra device into the open USB port on your keyboard? or is this on the back of your system?

    You cannot plug something like an iPod, some cameras, or even some card readers into the keyboard connection. The keyboard itself draws allot of power, and can only really support one other low power device such as a mouse, or other device with low draw.
  5. powers927 macrumors newbie

    Apr 2, 2010
    i have the same problem...but worse

    it all started with me puking on my computer in my sleep when I was drunk one night. I got some in the USB ports. This is disgusting, I know, but it was an accident and I can't do anything about it.

    The problem:

    I get that same message about my USBs drawing to much powers. It freezes my mouse up, and it drives me insane. This usually happens at least once every 5 minutes. Apple says it will be $800 to fix, which is crap because the laptop itself was $1000. Is there any way I can just disable the USBs so this will stop happening? I'm desperate, please help!
  6. Makosuke macrumors 603

    Aug 15, 2001
    The Cool Part of CA, USA
    Well, powers927, that's the second-worst cause of hardware failure I've heard of.

    Regardless, either there's some... stuff stuck in the port that's shorting it out, or the port itself got corroded and is shorting out internally.

    You might try getting some Q-tips and isopropyl alcohol (ironic, I know) and cleaning the inside of the ports thoroughly (while the computer is off and powered down). If that doesn't help, take the computer apart (which will be a challenge, but hey, it doesn't work anyway) and see if there's anything gross inside to be cleaned off. If so, clean, put it back together and try again.

    If it's clean and still doing it, see if you can maybe see the spot it's corroded and if you can scrape the corrosion off without breaking anything, to remove the short. Alternately, if that doesn't work and you've given up hope of anything else, you could try cutting the ports off the motherboard, though that runs a pretty good risk of breaking it completely.

    You could, alternately, try removing the USB-related kext files from the OS and see if that kills the error messages, though if there's still a short it might overheat or cause other damage eventually (assuming the ports continue supplying power even when disabled, which they may not).

    A Google search should lead you to what kexts are necessary, and you can use for the physical takeapart instructions.
  7. chkdg8 macrumors 6502

    Oct 24, 2007
    Don't want to start another thread

    I keep getting this message at least once a day now. All of my USB ports are taken. 2 external storage drives. My 1TB media drive uses my FW800 port and is powered via its own AC plug so that is no problem. My TM backup drive takes up a USB port behind the iMac and my left keyboard port for power. They're both less than 6 months old. Another port in the back of my iMac is for my Logitech MX1000 mouse and the third for my keyboard. All ports are claimed except for my right USB port on my keyboard which I use to sync and power my iPhone. Everything is up to date so I know it's hardware related. What can I do? This thread here is the latest information available on this subject except for one thread on Apple's discussion forum.

    I forget where I read that getting a USB hub with its own dedicated power source will solve this problem but then it said that you shouldn't have external drives connected to it. That doesn't make any sense to me. Can someone explain?
  8. Makosuke macrumors 603

    Aug 15, 2001
    The Cool Part of CA, USA
    The answer you found previously was correct.

    The problem is almost without question the drive that requires two USB ports. In particular the ports on a keyboard are not intended to supply anywhere near the max USB current possible--the keyboard itself draws power, and Apple didn't, at least in earlier hardware iterations, make any provisions for much extra available. Even some USB thumb drives won't work on a keyboard port.

    Your 2-port drive is going to be wanting a lot of power on its "power" port--depending on the drive, maybe more than the USB spec even technically allows (it's not uncommon). I've seen some cheaper drives that will actually shut an older Mini down entirely if you try to power them off its USB ports on account, I assume, of immediately drawing way more power than is available without properly asking for it.

    As for the solution, if your drive does indeed have TWO ports, that's the answer--the power port needs to be plugged into a powered USB hub, while the data port can go directly to the computer.

    In many cases plugging the data connection of a USB drive into a hub will actually work just fine, but even if it were to cause issues with your specific drive and whatever hub you get, so long as it's just the power port plugged into the hub, there won't be an issue--the power USB port is really just the power connections, it carries no data whatsoever. You could also plug it into an iPod wall power brick, or any other AC brick with a USB port on it, which is getting more and more common.
  9. Raytrace macrumors member

    Apr 2, 2010
    I get this message too but I'm trying to use an HP LP2475w monitor as the hub. It has worked sometimes in the past and then it decides it won't work.

    Well, if it has worked once, why would it not work the next time I boot??

    I'm about 99.9% sure there's nothing wrong with the hardware but my mac THINKS something's wrong. I'm using a 2008 MP btw.
  10. chkdg8 macrumors 6502

    Oct 24, 2007
    Well, I haven't received this warning since my last post. I am about to purchace a USB hub though because of my needs to expand external storage space. USB hubs will normally cure this problem as the Mac's keyboard ports aren't designed to provide sufficient power. If anyone can post a pretty decent hub for macs with good ratings, that would be great.
  11. petepajor macrumors newbie

    Jan 8, 2011
    I know this is old, but...

    Yes, I realize this thread is old but it's one of the only open conversations I could find on the topic. I am having the same problem as everyone else, and I am lost. I have a 2010 MacBook Pro and it was working fine until a few weeks ago. It has two USB ports and being a laptop there's no need for a keyboard/mouse hookup. When I do school work on it I use one port for my iPod and one for my flashdrive, and this shouldn't be a problem. However within the last few weeks whenever I plug both in at the same time it says that it's drawing too much power and disconnects my iPod. This hasn't been a problem until a few weeks ago and I'm not sure why it's happening. Any ideas?
  12. Rizomjo macrumors newbie

    Jan 9, 2011
    Me too!

    With an Mac Air (old), 10.6.6.
    It does only happen when I try to connect the external cd/dvd reader.
    It does not happen when I use at the same time tje Phone and flash memories even jointly with a hub.
    I have to conclude that there is something with the device that does not work.
    I will clean the usb of the dvd and tell you.
    Thanks for any other idea!

  13. Makosuke macrumors 603

    Aug 15, 2001
    The Cool Part of CA, USA
    Well, nothing has changed physically, so there are only four possibilities: There's something wrong with the computer hardware, there's something wrong with the iPod hardware, there's something wrong with the cable, or there was some software update that changed the amount of power allowed. I'm assuming here you've tried without the flash drive attached and get the same behavior--if not, do so, to rule out the flash drive.

    Software is exceedingly unlikely--the USB spec is very specific, it's all Apple hardware, and I think there'd have been hundreds of posts on the topic if a software update was causing iPods to not charge properly.

    Which means that either your computer is acting up, your iPod is acting up, or the cable is flaking out.

    I'd actually be the most inclined to assume that it's the cable, since the computer and iPod are (I assume) otherwise acting normally. It's easy enough to get a spare cable and test, so either borrow one from a friend or buy one and see if it does the same thing.

    If not, try just the iPod on the other USB port and see if that helps. If so, it must be a bad port. If not, try putting a powered hub (they're cheap, or you can bum one off a friend) between the iPod and the computer; if that fixes it, it's probably the iPod--the only way to be sure would be to borrow another iPod, plug it directly into the computer, and see if it works properly. It could be that the iPod's battery is going, if it's older, and so it's trying to draw too much power during charging, although I'd expect the iPod's internal circuitry to fix it.
  14. hi3ubq macrumors newbie

    Dec 5, 2010
    this happened to me too
    But when I use another cable to connect my USB hard drive and problem solved.
    Thanks Makosuke :)
  15. purplesaber macrumors member

    Nov 15, 2008
    This problem was driving me nuts until I found this thread. I bought a 2TB USB drive for my mac mini (2009 version) and it would sporadically be disconnected with the "USB port is drawing too much power warning) even though the USB drive IS powered with its own AC adapter. I bought a powered USB port and that worked better, but still had the same problem with the mini refusing to accept the USB connection periodically ("USB port drawing too much power").

    So I swapped in the USB cable from my printer rather than the one that came with the drive and voila! It works! The cable is thicker, but I don't know if that is why it works better. But anyway the winning tip seems to be to try a new USB cable when you get this error message.

    I really appreciate the advice in this thread -- thanks!
  16. Kaygie macrumors newbie

    Feb 22, 2011
    This worked...

    Thank you, forum, for providing the solution to my "...too much power..." error message. Changing out the cable from USB to my iPhone solved my problems!:D
  17. Autopulated macrumors newbie

    Sep 3, 2009
    You can disable the message (the device will still get disabled), by doing:
    sudo launchctl unload -w /System/Library/LaunchDaemons/
  18. Makosuke macrumors 603

    Aug 15, 2001
    The Cool Part of CA, USA
    Since the thread came back up anyway, a bit of info I didn't think about previously, in case others find the thread: Some of the built-in peripherals on Apple hardware are actually USB devices (for example, the iSight camera and built-in card reader, and even the keyboard and trackpad on some laptops). It's going to depend on the particular model, but if those built-in peripherals are actually on the same bus as the bad port, those built-in devices will flake out along with it.

    And my previous desperation suggestion of removing USB kexts would actually be useless; since it kills all USB, including any internal busses, it would kill all internal peripherals, which probably includes the built-in keyboard and trackpad as well, so the computer would be useless.
  19. BlueEyedAl macrumors newbie

    Apr 28, 2011

    ;)The fix is what you should do anytime your Mac does not seem to be functioning properly, reset PRAM. I have done this to a numer of Mac's and it worked everytime.
  20. Incubar macrumors newbie

    Jul 7, 2011
    New case 7-6-11

    Hi, how bout this one?

    For months I've been using a USB wireless signal booster.

    In the last week I'd gotten more and more "too much power" alerts, but today [7/6] it's permanently disabled on both usb ports.

    I'm definitely buying a powered USB hub this weekend, else you have any other tips???

    Thx all.

    13.3 MB Pro, early 2010 model.
  21. bradleydad macrumors newbie

    Oct 20, 2007
    Same message, all ports dead.

    This issue seems to be getting more common with MacBooks.

    "Because a USB device was drawing too much power from your computer, one or more of your USB devices have been disabled." pops up at startup.

    Resetting SMU and cleaning USB ports ineffective. No USB ports work.

    Any ideas besides "bad logic board, junk it"?
  22. macladie macrumors newbie

    Aug 8, 2011
    I think i fixed it

    Whenever I would plug in an ipod(any version) I'd get the same message. So I switched the ipod cable and the messages stopped!

    I have a Macbook 10.6.8
  23. Jasian macrumors newbie

    Sep 13, 2011
    Similar Issue

    Hey guys! I'm rather new to this forum, but i've owned Apple products for a while.
    Description of Device: I own a Macbook, the kind that is solid aluminum, my laptop was made before the Macbook Pro version existed for it. I believe that my laptop was manufactured in 2008-9, I don't exactly remember.

    Problem: I have a Blackberry but not a charger for it, because I lost mine. Since I didn't have time to go get one, I decided to build my own charger (I know it was a terrible idea in retrospect), I looked at videos all over the internet and got a good idea of what I was doing. I took a USB ipod syncing cable that came with my ipod, stripped the wiring, took the red and black wires out and stripped the insulation from those. I then took the Blackberry's battery and touched the red to positive and black to negative on the metal strips on the battery that allow the electricity to flow in/out. I then Put the battery into its proper place in the phone with the wires still attached to the ports so that the phone would have a constant power supply because of the circuit that is created through the phone when the powered battery is connected to the actual phone itself. I then plugged the USB into my computer and immediately got an error message saying something on the lines of "Your USB port is draining too much power, we're disabling the USB ports" thinking that this was a strange thing but not a bad thing, I stupidly tried it again and got the same error message again, and when I checked later i realized that the USB port had actually stopped working even when restarted the computer. My hunch is that i blew something out in the computer but I'm not exactly sure. The bottom line is, after seeing that people had to pay $800 for a repair, I wanted to get a very good diagnosis of the problem before i take farther action.

    Extra information: If i boot the computer while i have the USB drive for my optical mouse in one of the ports, the computer does not boot, it stays at the starting gray screen where it chooses the operating system. I also have both Mac OSX and Windows7 installed on my computer. The rest of my computer works fine, the only part that's affected is the USB ports. I haven't noticed anything else that's different with the functioning of the laptop.


    I just tried this and my iSight still works but all the USB ports do not
  24. Shlomit macrumors newbie


    Feb 1, 2009
    Born in Jerusalem, lives in Tel-Aviv,
    Got the issue here, Mac Pro, 10.6.8

    Dear all,
    Just wanted to say I got the same problem here,
    It happened suddenly, I disconnected all my USB devices,
    Still get this message.

    I did Pram as being suggested here and and now I don't get the messages anymore.

    Thank you for this advice.
    Now I need to find the problematic device.

    all the best
  25. charlie121 macrumors newbie

    Oct 16, 2012
    I know this post is old, but did you ever fix this this problem? Cause I did the same thing...please let me know!


    Hi, where do i put that code?

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