This is a follow up to my other question.

Now the problem is sometimes when inserting a USB stick, the computer freezes and goes to a complete gray screen(kernel panic). It seems to only happen if the USB is plugged in after it boots up.

It has been through two AHT runs, first run through was not extended and it gave only the error 4SNS/1/40000001: ID0R-0.000, which according to here that means a problem with an electrical sensor for DC power. That site recommended to reset SMC, so after that, another AHT was run, this time extended, and it gave the only error 4SNS/1/C0000008: TPCD-- 124 which apparently is a temperature sensor for the power bus.

I'm not sure what those would have to do with plugging in a USB though, maybe they could be related, idk.

Here is a kernel panic log right after an USB insertion http://pastebin.com/q3LWSWbS. Which I believe pretty clearly says it was indeed the USB that was problematic on line #33

32. Kernel Extensions in backtrace: 33. com.apple.iokit.IOUSBMassStorageClass(3.6)

  • Is it with specific USB only or any USB ?
    – Ruskes
    Oct 1, 2014 at 3:34
  • It was testing an crashed with 2 different ones, so I'm assuming any will do it
    – janka102
    Oct 1, 2014 at 4:01
  • you said sometimes,so not always? do you have another USB port?
    – Ruskes
    Oct 1, 2014 at 4:57
  • There are 2, and they both can cause the problem
    – janka102
    Oct 2, 2014 at 23:39

2 Answers 2


Based on this post and the other one at MacBookPro10,1 had problems booting, now some system images are pink and fuzzy :

I would say that you're probably looking at a faulty logic board. The system should be taken into a Genius Bar or an authorized Apple repair centre for further evaluation and/or repair.

  • oh great, yay. I was hoping it would't have to come to that, but I guess it did. Thanks for taking a look at this
    – janka102
    Oct 1, 2014 at 4:17
  • 1
    Yup - That graphic distortion on the other post is indicative of GPU failure and/or RAM failure - but it could be anything from the cabling to the display panel to the logic board itself. A tech that's current on that model will be able to give you estimates based on recent failure rates, etc...
    – bmike
    Oct 2, 2014 at 13:57

Since your AHT did not detect problems with CPU or GPU or RAM or Disk next step is to look at your Console log.

Based on the Console log you published it is your:

BSD process name corresponding to current thread: kextd

creating problems sometimes when you insert the USB.

The kextd is responsible for loading unloading drivers as needed.

Since it is possible to reset kextd without terminating and restarting it.

launchctl unload /System/Library/LaunchDaemons/com.apple.kextd.plist

Follow the description and procedure here:

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