mac won't startup

[jackie.werner]

Help, all of a sudden my mac won't start, it fires up, I get the apple logo and the startup bar but it takes forever, when it finally gets to the end it shuts down, what do I need to do and what could it be?

 

[bobtomay]

What Mac?

What version of OS X?

Have you tried booting while holding the shift key down?

"Assuming" you're running OS X 10.7 or later, have you tried booting while holding the command and R keys held down?

Have you tried booting to your cloned bootable backup?

 

[jackie.werner]

Am running OS X 10.7. What do you mean by cloned bootable backup?

 

[Slydude]

A cloned bootable backup is a copy of your hard drive that was made while everything was working well and has been saved to an external drive. If the copy is "bootable" you can start your Mac from the external drive by restarting, holding down the option key, selecting the external drive, and pressing enter.

 

[harryb2448]

Any odds on the answer being no? As suggested go the Recovery route and check out the hard drive.