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I'm getting timeouts on my USB every few seconds like this:

Jan  8 22:07:43 Thorstens-MacBook kernel[0]: USBF:  1722. 27    AppleUSBEHCI[0xffffff800b8b2000]::Found a transaction past the completion deadline on bus 0x24, timing out! (Addr: 6, EP: 1)
Jan  8 22:07:45 Thorstens-MacBook kernel[0]: USBF:  1724. 29    AppleUSBEHCI[0xffffff800b8b2000]::Found a transaction past the completion deadline on bus 0x24, timing out! (Addr: 6, EP: 1)
Jan  8 22:07:52 Thorstens-MacBook kernel[0]: USBF:  1731. 32    AppleUSBEHCI[0xffffff800b8b2000]::Found a transaction past the completion deadline on bus 0x24, timing out! (Addr: 6, EP: 1)

How can I figure out what is going on? Which of my USB devices may be causing this issue (other than disconnecting one after another)? What other ideas are there to avoid this problem? (Note: My USB hub is powered, which was one of the suggestions I had seen when googling the issue).


Here are the devices connected ty my Mac through a powered USB hub:

  • printer (HP Deskjet)
  • iPhone docking station
  • JBL iPod dock/loudspeaker (also powered)
  • a Pinnacle DVB-T antenna
  • a Garmin charger for my GPS watch
  • a Garmin ANT+ connector
  • an (unused) Logitech headset
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Can you give us a list of the devices that are connected to your computer with USB? –  Nathan Greenstein Jan 8 '12 at 21:22
edited the question to reflect my devices –  IronGoofy Jan 9 '12 at 7:37

3 Answers 3

up vote 5 down vote accepted

Generate a system report (in Lion: About this Mac-> More Info -> System Report, or do a Spotlight search for System Information if you allow Spotlight to index applications.)

Click on USB; then look for the bus ID mentioned. Under that bus, look through the Location IDs of each device; this field is "Addr" in the error logs. Note that location IDs are unique only across a bus, not the entire system.

Once you've identified the device, I would try swapping it to a new port, either with another device on the hub or to a blank port on said hub. If the errors stay with the device and not the port, my next step would be to plug the device into a direct port or swap cables. If you still have issues with the device, look for firmware updates to the device.

If after troubleshooting the hub is suspect - note that some people have found the power adapters that ship with some cheap USB hubs to be very poor, not capable of delivering anywhere near enough current. http://hackaday.com/2012/01/06/running-the-numbers-on-a-cheap-psu/

I would put the phone and garmin charger directly off the Mac's USB ports; among other things, your mac can supply twice as much current to your phone for charging. See https://support.apple.com/kb/ht4049

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Thank you very much, this helped me to nail down the device and get rid of the errors. Just the information I was looking for! –  IronGoofy Jan 9 '12 at 22:37
Out of curiosity, what was it? –  Brett Dikeman Jan 9 '12 at 22:39
It was the Garmin ANT stick .. I can only assume that it is polling for some new data and that the case where no new data is found leads to some issues. Removed it, no new errors. –  IronGoofy Jan 9 '12 at 23:00
I found the same this today with mine. –  cstrat Aug 7 '12 at 4:10
It seems that the issue only appears if the USB ANT+ stick is plugged in, and the Garmin ANT agent is running: forums.garmin.com/showthread.php?14436-Ant-Agent-2-1-6-2-Issues/… –  Matthew Schinckel Dec 6 '12 at 5:29

I can confirm my Mac's logs are filled with this error.

Take Garmin Ant+ off the Mac and the errors go away.


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Same issue here. Unplugging Garmin ANT+ fixed it.

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