Mid-2009 MBP Keeps Shutting down unless I keep holding option button

[ppz28hopower]

Hi Everyone -

Mid-2009 MBP. All stock hardware. I do not have any partitions. I do not have any external USB devices. I do not have applecare.

Started having issues a few weeks ago... When i power on the computer, it will get to the grey apple logo screen and then shut down. If i power on the computer and hold the option key, select the MAC OS, it will load normally. After about a minute, i get a re-occuring prompt asking me if i want to restart/sleep/cancel/shutdown the computer. (this is not the prompt in multiple languages, but the prompt you get when you press the power button). If i do not push cancel it will shut down on its own.

However, if i keep the option key pressed the entire time i am in the MAC os, i do not get the prompt asking me to restart/sleep/cancel/shutdown the computer.

Things I have tried with no avail: formatting the HD and reinstalling Leopard OS, apple hardware test (holding down the D button), PRAM reset, ive unplugged battery and ran straight from power supply, ive repaired disk permissions.

Any ideas??

 

[AFPoster]

You have a corrupt system file. If I were you I'd check for updates if it doesn't find anything than reinstall OS X. It will fix the issue, sorry you have this mess to deal with.

 

[kgallag1]

Could it be something's holding the power button down a bit, so mac os thinks you want to shut down?

You could try installing a replacement hard drive, and reinstalling Mac OS to that to see what happens.

 

[matthewscott661]

It sounds like the power button is being pressed or is broken in some way.

I tried pushing my power button while holding down the option key, and nothing happened, no prompt asking me what i wanted to do, so this is why you are able to keep using the computer while doing so. The option key is telling the computer to ignore the power button being pressed.

I don't know how good you are with computer hardware, but I'm sure there is a guide on ifixit that could help you out with fixing or replacing the power button.

 

[Andy Tabor]

Having the same issue with MacBook Pro 15"

Did you ever find a resolution to this issue?

I have a 15" MacBook Pro that keeps prompting to shut down. If i keep wiggling my finger on the touchpad or hold down the option key, it stays running just fine. I have reset SMC & PRAM, disassembled the power switch & checked it for interference.

Genius bar thinks "the entire top cover assembly needs to be replaced to fix the power switch", but the power switch does not seem to be at fault.