Unable to mount Macintosh HD

Welcome to the Apple Support Communities

If your Mac tried to start in safe mode and it turned off, OS X couldn't repair the hard drive, so it's damaged. I recommend you to install a new hard drive as soon as possible. If you want, you can install one yourself, buying the HDD in OWC > http://eshop.macsales.com/shop/hard-drives/2.5-Notebook/ You can find the steps to install it in the same site.

All hard drives fail because of their use, the temperature, how you took care of your computer, etc. Those problems happen

OS X v10.6- Gray progress bar appears under Apple logo during startup.

Please do not attempt to partition the drive or make changes to it using Ubuntu. The following will not affect your Boot Camp partition, but if you fiddled with the drive using Ubuntu you may lose the ability to boot into Windows the usual way.

Take the advice of Disk Utility and backup your files. You will not have to partition the drive, but you will need to reformat it:

Install or Reinstall Lion/Mountain Lion from Scratch

Be sure you backup your files to an external drive or second internal drive because the following procedure will remove everything from the hard drive.

Boot to the Recovery HD:

Restart the computer and after the chime press and hold down the COMMAND and R keys until the menu screen appears. Alternatively, restart the computer and after the chime press and hold down the OPTION key until the boot manager screen appears. Select the Recovery HD and click on the downward pointing arrow button.

Erase the hard drive:

1. Select Disk Utility from the main menu and click on the Continue button.

2. After DU loads select your startup volume (usually Macintosh HD) from the

left side list. Click on the Erase tab in the DU main window.

3. Set the format type to Mac OS Extended (Journaled.) Click on

the Erase button and wait until the process has completed.

4. Quit DU and return to the main menu.

Reinstall Lion: Select Reinstall Lion/Mountain Lion and click on the Install button.

Note: You will need an active Internet connection. I suggest using Ethernet if possible

because it is three times faster than wireless.

Upon completion of installing Mountain Lion you can go about restoring your data from your backup.

In that case, as I told you, replace the hard drive. Even if you can reinstall OS X and continue using it, the hard drive is failing, so you should be careful

Could not be mounted or could not be unmounted? When DU is formatting or partitioning a drive it first unmounts the drive.

If you are opening DU and it says it cannot mount your drive, then you will not see a drive listed in the sidebar. In this case the drive has failed and will need to be replaced.

But it the drive is in the sidebar and you get the cannot unmount error then it may be because you did not first boot from the Recovery HD.

You need to clarify what the exact circumstances are before one can state the drive is bad or just needs to be reformatted. Thus far the evidence for a failed drive is inconclusive despite the assertions of my esteemed colleague, mende1, although he may yet be proven correct.

And, you did this while booted from the Recovery HD from which you ran Disk Utility, correct?

If you select the grayed out volume try clicking on the Mount icon in the toolbar. Is the volume still grayed out? If you select the topmost item for the drive and then look for the SMART status in the lower status area of DU, is the status Verified? If not the drive has failed or is failing.

If you make no progress past this point then you should take it in for repair and have the drive replaced.

I'm sorry that finally the problem is the hard drive. All the cases I have seen before similar to your problem had the same solution: a new hard drive. That's why I told you to get a new hard drive instead of trying to repair or erase it, because it would be unsuccessful. You are welcome

Sorry I couldn't help more. Sometimes hardware just fails and cannot be fixed.

Do online recovery through apple servers directly.. it is generally a problem of disk utility.

i have faced the same problem..

Shut down the macbooh..Press & hold Command+alt+R & power on your macbook.. it will automatically start the online recovery.

it will download some 400 mb of data..(mine got downloaded in 30 mins)

after it get complete, you will get an option to go into disk utility.. go into that.. select your hard disk from the left panel..go into partition tab..in layout choose one partition.. format as extended(journaled).....& Apply..

there you go..it will format your HD..

now you can install fresh OS on it..

there is NOOOO ******* apple service in my area and I solved the issue of chime now there is a startup tone but still the bar is there which takes time and after completion requires restart and again starts so this cycle goes on.

I checked HD and that is fine from diagnostic evaluation

I don't have any apple service please help me

Now my issue is I get a grey bar blow apple logo on each startup and it takes 15 to 20 min and than MBP stops that requires again manual restart and again that grey bar

That possibly means that there is no os loading at the startup

Thanks

Hi, first time posting here, apologies if my knowledge of Macs is poor.

I have recently acquired a MacBook Pro (early 2008) and I have the same problem as above. Booted up and the grey/gray bar appeared for the first time.

Booted this evening with Snow Leopard DVD.

Ran Disk Utility and I get "Incorrect number of thread records", and it tries3 times and issues an ERROR: Disk Utility can't repair this disk. Backup as many of your files as possible.

Nows the question - how.

How do I backup files from a drive that is not mounted. I thought I could use the Restore tab and after formatting a 64GB USB Flash drive as Mac Journaled, I could use Source - My problem HDD and Destination my just formatted USB Flash drive. But the Mac HDD is Grayed/Greyed out.

Any suggestions would be gratefully received.
Paul

Problem solved, i used online recovery to retrieve the necessary instalation files then deleted the main partition and created a new one using disk utility before installing mountain lion back on to the mac... I am sendning this message with the mac that has been down for 2 days. Apple customer care need to go back to mac school...