Hi am trying to fix a MacBook Unibody Model A1342,

The macbook has an unknown error that might also be caused by water accident or drop or just internal problems. (I dont know about the macbooks history)

i try to describe everything detailled:

normal startup ends on blinking folder with "?"
    shutdown after this is only possible with long press on power button
        restart after this is only posiible after PRAM reset
AHT test ends without errors
Internet recovery starts
    sees Wifi networks
        doesn't connect after correct Wifi-Key
            works with ethernet
                loads all data (progress bar)
                    starts until i see grey "fabric" background for a very short time and then the system suddenly shuts down.
all this is reproduce-able

Tried second hard-drive and got this error: enter image description here

Does anybody have any suggestions?

  • shutdown after this is only possible with long press on power button ***will reset the SDC !
    – Ruskes
    Jul 13, 2013 at 8:19
  • That symbol you are seeing means the system can't find an OS to boot to. Most commonly this is a bad drive as you suspect. It can also be a bad drive cable or bad logic board, but this is much less common. Use disk repair to fix it.
    – Ruskes
    Jul 13, 2013 at 8:22
  • Whats an SDC? Doesnt AHT test the drives?
    – nurx
    Jul 13, 2013 at 8:38
  • Sorry a typo, SMC :) System Management Controller. To test drivers try the safe mode. I think you have a hard disk problem not drivers problem, and yes the AHT will test drivers.
    – Ruskes
    Jul 13, 2013 at 8:47
  • Okay. I tried it with a different HD. Same Problem. When i start verbose these lines are the last before sudden shutdown: imageshack.us/a/img12/4290/szwn.jpg
    – nurx
    Jul 13, 2013 at 12:48

1 Answer 1


Boot the Mac from a known-good local OS.

You can install an OS on to USB drives (HDD, SSD, flash) or even set up a local net boot server, but you'll need to get logs of how far into the boot process the computer gets to diagnose what subsystem is failing.

A hardware technician might remove all of the components that are not needed to boot the system and ensure that the RAM and logic board are working, but I wouldn't recommend starting hardware diagnosis before you've finished the software analysis and brought a known good OS of a proper version for your Mac to the suspect hardware.

  • i tried to boot from a harddisk with recovery and from a usb ubuntu drive. Both shutdown very early. Ill try to remove the ram one after the other next...
    – nurx
    Jul 13, 2013 at 17:11
  • Bad RAM that is bad enough to prevent boot on multiple OS usually gets flagged in POST with three beeps, but it's worth a shot. It sure seems like a hardware issue from this additional information about how it won't boot any OS when Apple's internet recovery and recovery HD are very sure fire minimal systems designed to boot even half-broken systems for maintenance and diagnosis.
    – bmike
    Jul 13, 2013 at 17:19
  • tried both rams, both failed. I found some very little dirt on the logic board. that might be caused by liquid. maybe i have to disassemble and clean it all up...
    – nurx
    Jul 13, 2013 at 17:34
  • just thinking about the good aht result. how can that be? there was no failure...
    – nurx
    Jul 13, 2013 at 18:11
  • I don't consider AHT very useful in my experience. It tests a few things very well, but lots of problems fly over or under its radar.
    – bmike
    Jul 13, 2013 at 21:22

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