I can't install Mountain lion. It says my HD is locked

I'm having the same issue!

You might try repairing the disk with Disk Utilities.

Nothing will have been installed at this point, so you should still be able to boot to your old Lion install, or the Recovery HD.

I have the same problem; my macintosh hd is locked, and cant be installed with mountain lion. Now, my computer is totally dead. I think I accidentally erased the HD. After repairing the HD, I am giving a try to see if I could install mountain lion. Otherwise, I may ask for a refund. I hate mountain lion 😟

I could have sworn I saw a post where someone else had the problem and AppleCare had them erase the drive and reinstall, then migrate from the backup. However, I can't find it, now.

How did they make that determination?

Drives fail. There isn't really anything that can predict when. Some last years and years and some die pretty quickly.

The SMART status watches the drive for signals that might mean failure. The results of those checks shows up in Disk Utility at the bottom of the screen. It should say verified. However, I had a drive that was acting strange. It was having trouble reading a certain sector and would hang up the machine. Repairing the disk and other things would fix it for a small time, then it would start up again. SMART status was verified the whole time until the drive pretty much stopped.

I had the same thing happen when I attempted to upgrade from Snow Leopard. My files are not gone. (It loads the installer off the disk. So the disk is working.) I rebooted in Single User mode (held down command S during bootup). Following directions at the prompt and using fsck_hfs revealed that my disk is write locked!

Now things make sense. The OS installer write locked the drive. That is why the diskutility can't repair the drive! Genius bug!!! I took the drive out of my power book, put it in an external enclosure, plugged it into my old Mac Mini and am backing it up.

Even the genius instructions reveal the drive isn't bad: 'backup and format'. DUH! Why would they tell you to use a bad disk in the future. It isn't bad. It is write locked. Thanks! Not what I expected. How do I remove the write lock? Come on, backing up through USB, then writing back through USB is going to take 20 hours. This bug is wasting my time!

These aren't drive failures. They only happen every time I update the opperating system! The drive may need a fsck before installing the OS, but can't be fixed while write locked. Nobody told me to fsck before updating the OS, and nobody told me how to remove the write lock. Where is the manual?

I had a similar issue. I can't recall all the steps, the solution just occured to me right away and I didn't pay much attention.

I was trying to install from a partition on an external drive. I got this error message, similar to yours; I chose to quit and it brought me to a screen to select what drive to install from (there were icons of the two drives side by side); I chose my Mac's HD and it requested my Admin password, which I entered; there was another step after that where I could cancel again and got back to the same screen where I could select which drive to install from; I chose my external drive. This time I didn't get the error message.

Hope this will help, sorry I can't be more precise.

So, because they couldn't understand the problem, they told you the drive was failing?

I read somewhere else that they told them to erase the drive and reinstall, then migrate from backup. Can't find that post, now, though.

Are you trying to Erase it or Partition it? With it indicating Locked, you likely can't Erase it. However, you might be able to partition it.

But, if the drive is dead, there's not much you can do but replace it.

I would recommend you try restarting your computer while holding down the Shift key. Once restarted look for the Mountain Lion installation folder and restart the installation from there. I had a similar glitch when my install was interrupted and that seemed to solve it. It went on to a normal installation.

Good luck.

The fix is not in terminal, it's not some command . . The way to unlock a drive in disk utility is to double click on the locked drive in the left column. You will be prompted for your admin password. Enter it in, and that's that.

I stumbled upon it by accident when I hit the same wall trying to do a clean install of Mountain Lion, and once I unlocked it, I was able to erase my Lion partition (AFTER BACKING UP OF CORSE), verify the hard drive, then format that drive, and now, no more Lion. Actually, once you do the previous steps, there's no more anything after you erase and format, until you install the new OS X.

:-)

My mountain lion was locking my drive had to erase everything but on trying to reinstall using a firewire though my macbook pro it kept reading the drive as bad. I got out my snow leopard disc and did and install from that and it worked fine. Mountain Lion is the issue! Reinstall snow leopard!