Strange OSX Crash...
October 17, 2010 5:58 PM   Subscribe

MAc OS X 10.6.X Won't boot PLEASE HELP!!! So the MBP17 (Late 2009) crashed while watching netflix in FF3.x I thought no problem, just reboot and watch the next episode...Oh how wrong I was, now it won't boot. Details after the jump.

When I try to boot I get the gray screen with an apple that turns to a gray screen with a circle and slash -- like a no smoking sign.

So tried rebooting with the option boot, it sees the drive, then goes through the gray screen cycle of apple to circle/slash.

So tried booting into Verbose and Single User mode, I get the same error each time:

Cannot Mount Root Errno=19

Which comes over and over.

So I booted with the Snow Leopard install disk and tried to repair the disk and got:

Checking Journaled HFS Plus Volume
Invalid B-tree node size
The volume could not be verified completely

ERROR: Disk Utility can't repair the disk

So I thought "well crap, now I have to archive install" but when I go to install there is no drive/partition to install into.

Back to disc utility, looking at the drive list on the left, I see the partition under the HDD, but when I look at the partitions under HDD>Partition I see the partition. Though it will not tell me how much space is used, etc. But when I look at the drive, the SMART Status reports verified.

So now I am out of OSX-Fu and need some help. I can use the target drive and move all my stuff to a separate Mac, then erase, format, reinstall everything, but what a pain in the ass.

Do I have any other options?
Why did this happen?
How do I keep it from happening again?

Thanks for any and all help.
posted by AnOrigamiLife to Computers & Internet (8 answers total) 1 user marked this as a favorite
Best answer: If the partition is corrupt (which it is) you can't simply re-install OS X. You need to backup your data and reformat the disk, which will probably fix it, but it will also delete everything on it.
posted by Mwongozi at 6:26 PM on October 17, 2010

Do I have any other options?

Try DiskWarrior or Data Rescue. Data Rescue has a free demo that will show all the files it can recover and will recover 1 file of 5MB or less to show that it works. People have reported success with both of these programs in cases like this. However, be aware that others have reported that sometimes they don't work.

Why did this happen?

The part of the drive that stores the B-tree node size data got corrupted. That little bit of information is vital to OS X being able to use the drive. It basically tells OS X how big each piece of each file is. Without it, OS X can't make heads or tails of the rest of the data on the drive. Luckily, it can only be one of a small number of possible values, so what the repair programs do is try each of them until it gets something that looks sensible.

How do I keep it from happening again?

Keep regular backups so that if this (or any number of other things) happens again, you can just restore from backup if you're unable to fix the problem. I recommend buying an external drive and using Time Machine or SuperDuper.
posted by jedicus at 6:27 PM on October 17, 2010 [2 favorites]

Best answer: nthing DiskWarrior and Data Rescue. I've used both of them professionally with excellent results as long as files haven't been overwritten, which seems unlikely in your case. If memory serves, you'll need an external drive to recover the files to.
posted by MonsieurBon at 7:56 PM on October 17, 2010

Best answer: DiskWarrior will fix this. I've had the b-tree node crash before and it's worked every time. Don't know about Data Rescue, but DO NOT use Drive Genius for this purpose.
posted by drpynchon at 9:54 PM on October 17, 2010

Best answer: This is the reason DiskWarrior was created. Best $99 you'll ever spend.
posted by fourcheesemac at 4:43 AM on October 18, 2010

Response by poster: Ok. So I created a bootable external hard drive from my install disk. The MBP boots just fine now from the external drive, but does not see the internal drive. I was hoping to be able pull some of the data off before messing with DiskWarrior. Any thoughts?

Is there a way to see in to the internal drive? Disk Utility sees the internal drive when running from the external drive.

Any thoughts?

posted by AnOrigamiLife at 12:13 PM on October 18, 2010

Response by poster: Update 1: I was able to use Disk Warrior to recover crucial files from the internal drive. Next I will report on the replace feature of Disk Warrior.
posted by AnOrigamiLife at 1:37 PM on October 18, 2010

Response by poster: Update 2: The replace feature did not work, but left me with a workable EFI image that I then used to reinstall OSX. Success!
posted by AnOrigamiLife at 3:43 PM on October 18, 2010

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