Has anyone tried this for the Random ShutDown issue ???

Yes. I have. It didn't do a thing. The machine did not go through a full start up the very next time I turned it on after I did that. If there was a fix suggestion on these boards, or on some other board referenced from these boards, I have tried it. Nothing has made a difference.

My solution has been to hold the power button until it beeps when turning the MB on. When I do that I can get the machine to fully boot up, log in and start running programs without incident. Now I can't tell you if I am screwing something else up by doing that, but at least I am able to get my MB to finally turn on and use it.

I dunno, that beep sometimes was magical in actually getting the machine to boot OS X.

Nick

Holding down the power button until it beeps is still the only way that I can get my machine to boot up fully and become operational. I was starting to think that I was crazy after reading above that all it did was to remind me that my finger was still on the power button. I've had my husband and my son watch this process just to convince myself I wasn't crazy.

I've been deleting software, going through log files, making other changes to make sure that they weren't interfering with the machine working. I shut the machine off this morning to go do something else. When I turned it on again I forgot to hold the power button until I heard the beep. After I logged in, I realized that I hadn't done that and that the machine had actually gone through the complete boot cycle and login. I thought "wow, maybe I fixed it. Maybe it was something software related." I waited for a few minutes to make sure that everything that it had to do in its start up was finished before I did anything thinking "well maybe its just that I try to do too many things too quickly, and it is operator error and my fault I've been having this problem". Then I went to open Safari and "blink" the machine went dead.

Then I put my finger on the power button until it beeped to start it up a second time. I've been working on it for six hours now. It's gone to sleep while I've been on the phone, I've woken it up with a short press of the power button and logged in a few times today.....not one single problem in 6 hours.

It's crazy. I don't know what holding the power button for that long does but it must be resetting or otherwise doing something that causes it to override whatever problem was causing it to just shut down by itself. I love everything else about this MacBook. I don't want to have someone start taking it apart and putting it back together again. If the fix is just remembering to "hold power until it beeps" I"ll live with it.

I had four or five random shutdowns last weekend. Then I started the machine by holding the power button down a few seconds (though not until it beeped). I've had the machine on continuously (on AC power) for about four days now, occasionally under very heavy loads, and (knock on wood) it's been running fine. Odd, but I'm not complaining!

Have you shut down your machine much since trying this? I'm wondering if frequent heat-ups and cool-downs might put a strain on the hardware. Not that that explains the power button thing - maybe it needs that extra few seconds to reset something.

Holding down the power button until it beeps is still
the only way that I can get my machine to boot up
fully and become operational. I was starting to
think that I was crazy after reading above that all
it did was to remind me that my finger was still on
the power button. I've had my husband and my son
watch this process just to convince myself I wasn't
crazy.

If the beep really is just a reminder, then there ought to be something else going on here. One guess would be that something's loose, and pressing the power button keeps it in place. Have you tried pressing the plastic beside the power button when starting it instead of holding the power button down?

If I recall correctly, the beep is the signal that the firmware install program has begun operation. If you had downloaded a firmware update and launched it, it would tell you to shut the Mac down, then turn it on and hold the power button down until it beeps. The new firmware would then install, the computer would reboot on its own, and then tell you its firmware was updated via a dialog box once it finished booting.

Perhaps holding down the power button has some effect on the current firmware, such as resetting it to default values or reinstalling it from some source (file on the HD, duplicate on the logic board, Mars).

If the beep really is just a reminder, then there
ought to be something else going on here. One guess
would be that something's loose, and pressing the
power button keeps it in place. Have you tried
pressing the plastic beside the power button when
starting it instead of holding the power button down?

Talking to myself here... 😉
I have the same problem myself now, and I tried this. It doesn't work. It seems that it's not the pressure that does it, but something else.

I like you're thinking. Whenever I use the press/hold power button procedure to get the macbook to boot up (since I am also experiencing random shutdowns even after logic board replacement), the fan seems to spring to life to max speed and then slowly ease off to idle. I never experienced this before when I simply tapped the power on button. It would seem to indicate press and hold activates a slightly different boot up process.

I don't think it's a software issue.

I've vaguely heard of the random shutdown issue from tech sites but didn't take much notice to it until yesterday when it happened to me (that's always the case though isn't it!).

It was connected to the power supply and it just shutdown randomly.

This morning, it was running on battery power and it shut down 4 times in a row.

I was using it for about 30 mins before the first occurrence, then when I go to switch it back on, it shut down again almost immediately after I pushed the button, this occurred 4 times before I stopped and when 'huh, maybe the battery is dead', so I tilted my Macbook to check the battery: 2 bars left, so it wasn't a lack of power issue either.

When I put the Macbook back down and tried it again, it switched on and booted up (super fast, faster than usual!) and now I am writing this post, on battery power, with ~1.11 hours left, wondering what the **** is going on??

It resets the firmware