Problem with MacBook booting to OS

WithCheesePlease

Have a very strange and seemingly intermittent problem with a macbook not booting and loading OS properly. When I turn it on the screen lights white and I see the little spinner - but before it goes to the blue login screen the screen blacks out. If I hit keys I hear a dull key tone and pressing the caps lock button toggles the LED.

I've tried booting from the MAC OS disk and that runs fine. All the check disk features run fine and show no problems.

Selecting to load Mac OS from the hard drive from the Mac OS disk option will load it up fine. But turn the mac book off and try to restart again and the same problem arise. It's as if the boot loader is getting lost and not finding the OS to load straight from the hard disk.

Any thoughts?

Alanstrainor

Moved to the Mac forum.

Sad Professor

Do you have a Windows partition?

WithCheesePlease

No, just a straight mac os install.

Sad Professor

Try selecting the OS X drive (it should be the only option) in System Preferences > Startup Disk. If that doesn't work try resetting the PRAM.

http://support.apple.com/kb/HT1379?viewlocale=en_US&locale=en_US

WithCheesePlease

Sad Professor wrote: »

Try selecting the OS X drive (it should be the only option) in System Preferences > Startup Disk

Is that after I start the macbook up with the os install disk in? In the disk utility screen? Or how do I get at the System Preferences > Startup Disk options?

Apologies - this is the girlfriend's macbook, I don't know the first thing about macs!

But thanks, will try these suggestions this evening...

Sad Professor

When you are booted up normally.

WithCheesePlease

How do I see that option when I boot up normally? Is there some combination I need to press to bring up a bios screen?

Sad Professor

There is no BIOS.

You just open System Preferences from the Apple menu.

WithCheesePlease

Ah right, thanks. The only way to boot in to get to the Apple menu is by going via the mac os install disk and selecting the start-up disk that way - kinda like what you've suggested. Just starting up the macbook alone isn't loading through to the OS.

But I'll play around with it and try what you suggested with resetting the PRAM later. Thanks for the help.

Sad Professor

WithCheesePlease wrote: »

Ah right, thanks. The only way to boot in to get to the Apple menu is by going via the mac os install disk and selecting the start-up disk that way - kinda like what you've suggested. Just starting up the macbook alone isn't loading through to the OS.

Try holding the alt key on startup. That should give you a choice of what disk to boot from. If the Startup Disk method works then that should as well.

yer man!

It may be a problem with the hard drive cable, macbooks are notorious for faulty cables. Mine was repaired last year after the macbook wouldn't boot to OS and would crash intermittently or if a moved it too much etc. You could try taking out the hard drive (doesn't affect warranty I assure you) and placing it in an enclosure external to the laptop and boot from that, then you'll know if it is the cable or not.

muggyog

You could try booting in single user mode ( hold down 'apple' and 'S' keys while powering up). You will get a text based command line display if you do it correctly.

Once the text has finished loading type sbin/fsck -f(dont forget the space) and press return. The Mac will do a FileSystem ChecK. See if it reports/fixes any errors.

To boot into OS X type logout or exit.

You could also startup in verbose mode ( 'apple' and 'V' on startup ) and you might see why its not starting up correctly.