the USB device drawing too much power has been disabled.

The USB2 spec states that the max. current available on the plug is 500 mA. That's why some devices from the PC world sport a strange two-headed USB cable, so they can suck the whole Amp from the computer.

But in this case, if the power management is deciding there's too much power drain from the get-go with nothing plugged in, there definitely is something wrong. Mind you, some of the components on the Mac are internally connected to the USB infrastructure, such as the trackpad, camera, etc. I'd suggest the following:

1. Reset the SMC: http://support.apple.com/kb/HT3964
2. Run the extended Apple Hardware Test: http://support.apple.com/kb/HT1509
3. If all else fails, schedule a visit to the Apple Store. Hope the Mac is still under warranty.

Take a screen shot of this message and take all the items to an Apple Store Genius bar. They should be able to diagnose the problem.

Have you attached other peripherals and if so has the same message appeared?

Ciao.

My wife's Mac pro is doing the same thing when she hooks up our canon camera. She has downloaded 1000's of pictures without problems before and now that message pops up . Also the SD card reader isn't working. When the card is plugged in nothing happens and we can't find the card in iphoto. So now she has no way to get the pictures on iphoto. It's not the cord or the card because I can download them without any problem on my windows computer. I also have seen a bunch of other post about this problem. Any help would be great. Thanks.

I don't have anything big to add to this, except my MacBook gets the same message when booting up. There is nothing plugged into the two usb ports and they don't work even with a powered hub plugged in. I do have an external, powered, 2.5" hard drive that works, but nothing else works. The internal camera, the keyboard, and the trackpad work, which are all usb. I figure it must be some problem on the logic board. This is a well travelled MacBook, so it looks like it is time to buy a new MacBook Pro after I see what happens on June 11, 2012.

Message was edited by: bbritton

I'm getting it on my Mac mini (Intel 2.53GHz, 10.8.2) despite having unplugged every USB device (I'm using a wireless keyboard and mouse). I get five of the windows open at a time. Close them and they reappear about 30 seconds later.

I've been getting the same issue for weeks now on my new 27' iMac (late 2012). Its driving me crazy, I've done all the resets and even an os x reboot. I constantly get the error with nothing plugged in. I've used different power cables and wall circuits to see if I could isolate anything causing the issue. I've brought my iMac to an authorized repair center and after they 'tested it hard' for 4 days they were somehow 'unable to recreate the issue'. So I brought it back home, booted it up and it instantly happened and has occured 100% of the times I've booted since. This is rediculous. Here is a video of it as well: http://vimeo.com/65979238

It even happens on Hackintoshes (suggesting it's a software problem):

http://www.tonymacx86.com/general-help/78759-usb-device-drawing-too-much-power.h tml

I've had it on two different Mac Minis, even with no USB devices attached. Turning off and unplugging for a few minutes before re-starting sometimes fixes it but there's no common cause. Hasn't happened to me for a few months, though.

rogerh2 wrote:

I've had it on two different Mac Minis, even with no USB devices attached.

No USB devices connected never happens, this is a report from an MBP with nothing plugged into the USB ports, but there are still 4 USB devices 'connected' (as you can see from the report)

Any one of those can be defective and that could cause high current drain from the USB bus.

I saw this error attempting to charge my Kindle. It worked very recently, and then suddenly the kindle was failing to charge on any USB power source so I was sure it was not my mac. I peeled open the USB charging cable because it seemed like the only common piece. Much to my surprise, I found a piece of broken pencil lead inside the USB plug, shorting out the 4 conductors. I turns out I'm happy to have the curcuit breaker on the mac shutdown the USB port. Of course I need a new cable now...

Anthony Acock wrote:

I have an external monitor attached to my laptop.

Well there it is there, power draw is a power draw.

What you can do is buy a powered USB hub and that will remedy your problem.

also do a SMC reset

https://support.apple.com/kb/HT3964

And what do you have plugged into the USB port? A coffee warmer?

No I'm not kidding. Some one else posted about that same error message and it turned out he had a coffee warmer connected to the Mac USB port.

If you are that poster or you have a coffee warmer connected thenn disconnect it and drink your coffe faster and or use a thermos mug.

I'm having that problem, too, but with a 2010 MacBook. I've been getting that error message periodically—including when I first power up my computer. The thing is, I have only two USB devices plugged into my laptop, and both are powered USB hubs. The only thing plugged into one of those hubs is my iPhone charge cable, and my iPhone's not attached. The other hub is attached to my Apple keyboard and a printer (the printer, of course, has its own power).

Another thing is, the Apple keyboard works, even after I get that message, so apparently it's not the thing that's being disconnected to save power, yet it's the only thing that doesn't provide its own power.

Any advice? Otherwise, I foresee a visit to the Apple Store in my future.

I just had my MacBook Pro give me the "USB device drawing too much power" warning, too. The problem is that it disabled my connection to an external hard drive while the drive was spinning. Gee, thanks, Apple - next time how about a chance to eject the drive correctly and protect my data?

When did this benevolent USB power grab start? I've never seen this warning before, and I haven't added any USB devices to the lineup for at least six months.

Anthony Acock wrote:

Thank you for a real answer! 🙂

I will next one that pops up. I have an external monitor attached to my laptop. But it seems to running fine. 🙂

You have an external monitor connected to a USB port?

Anthony, did the SMC reset change anything?

Courcoul has sensibly reminded the assembled multitude following this thread that the built-in keyboard, trackpad, camera, SD card reader, and possibly other internal things I'm forgetting (because I'm posting from my iPad and not my MBP) are all USB devices, and if one of those is malfunctioning it could be drawing excessive power. The culprit need not be external.