hanginstallmacossnow leopard
The screen I'm on does not have a time remaining estimate, that was the prior screen.
This one simply shows the Apple logo and a plain status bar with no percentage or time indicator.
Perhaps it's just the boot up screen.
At any rate, it's been stuck exactly at the halfway point for about an hour.
No clue what the proper course of action here is.
It's a 15 in MacBook Pro, mid 2009, Latest version of Snow Leopard with no history of install related or hardware issues at all.
One more thing to try: Boot in Safe mode holding the Shift key at the startup sound. If the internal drive is bad (failed drive or borked OS), this won't work.
If you have an external drive as a full bootable backup (and I hope you do), connect it a power it up. Then try booting the Mac holding the Option key, and select the external drive.
If you have another Mac, connect the sick Mac to it and boot the sick Mac in Target mode (hold the "t" at startup sound).
If either works, copy all critical data to the drive you are booted in.
I agree that there is at least one hardware failure involved.
offers to display both percentage and Time. http://bjango.com/mac/istatmenus/
When running SL, you could get the old free version. However, it does not contain the battery menulet: http://mac.brothersoft.com/istat-menus-2.0.html
Best Answer
This appears to be a variation on the boot cache problem with initial upgrade installations of Yosemite.
The difficulty for solving it appears to be knowing precisely when to press and release the Shift ⇧ key to enter Safe boot mode, which remedies the problem.
The procedure is explained in this Apple KBase article.
Shut down the computer by holding in the startup button until it powers down. Start the computer, and immediately upon hearing the startup chime (or when there’s any sign of life such as the sound of a fan, or hard drive, or lighting of the screen), press and hold Shift ⇧ . When the gray apple appears, release Shift ⇧ . After a few moments you will be prompted to log in, and the words “Safe boot” will appear in red letters near the top right corner of the screen.
Be sure to apply the latest OS X update before shutting down or restarting again if your version of OS X is older than 10.10.2. At the time I’m typing this, 10.10.2 is the current version. Having 10.10.2 should prevent the problem from occurring more than once.