Can't reinstall OS X - "This disk is locked"

SOLUTION: Guys don't waste your time. I had this exact problem but I tried using command + alt + r during boot up. Hold it till you see the globe pop up and let it do its thing and that should fix the problem (at least it did for me). Then you can install without problems. Good luck!

If didnt work buy an external hard disk and connect it to your mac and go to disk utilities and go to ur old hard drive then go to restore ,if the sorce is your hard disk name so thats ok usually its macintosh hd and in the other side destination grab the new hard disk, the new hard disk is gonna erase and copy the old hard disk so you are gonna have a back up ,when it finishes go to ur old drive theb click erase it will work ,you must put it on macOS (journaled) or the first option then just do the same on the first and it will work.

Good luck

You might want to consider starting a new discussion. Since this one is a couple of years old, less people are likely to look at it. A new post would be much more visible. You can link to this one.

Try using Disk Utility/Restore to copy the data to a new location. Please note that this will reformat the destination partition.

Boot to the Recovery Volume (command - R on a restart or hold down the option/alt key during a restart and select Recovery Volume). Run Disk Utility Verify/Repair Disk and Repair Permissions until you get no errors. Then re-install the OS.

OS X Recovery

OS X Recovery (2)

I'm writing this as I search for it and found solutions and none of them worked and I noticed I wasn't the only one.

Easy solution is hold down command + R and get into disk utility, select the main HD and select File > "Enable journaling" but if you are like me, it was greyed out. What the issue is, you are trying to modify the drive you are currently working on which it doesn't like. You need to create a USB flash installer, then reformate the drive then reinstall. The steps are below

Step 1 (i found step 1 at https://lifehacker.com/how-to-make-a-bootable-macos-sierra-usb-flash-drive-17868 53248:

The easiest way to create a USB flash installer is with the free program, Disk Creator.

1. Download the macOS Sierra installer and Disk Creator.
2. Insert an 8GB (or larger) flash drive. If you have any other data on that flash drive, back it up now, because the installer will delete everything on it.
3. Open Disc Creator and click the “Select the OS X Installer” button.
4. Find the Sierra installer file. This is should be located in your Applications folder.
5. Select your flash drive from the drop-down menu.
6. Click “Create Installer.”
7. When it’s done, insert your USB drive into any Mac, then launch the installer by holding down the Option key

Step 2 (now that you are booted on a the USB stick and not the main HD):

1. Once it loads, go into Disk Utilities and Erase the main drive and select the journaling formate style.
2. Then choose to reinstall the OS and the disk will not be greyed out this time.

Thanks for the tip. This is the way I solved the problem, but the first flash drive I tried didn't work, I was always getting the Block Screen, with the ∅ symbol. I tried all alternatives suggested here, but it only worked when I changed the flash drive, no idea why.

I almost gave up on my hard drive and almost wiped it clean.

Background: I upgraded the archaic spin drive to a 1tb SSD in 2013 iMac months ago. Something possessed me last night to hit upgrade to High Sierra.

The download went fine but when I said install the computer got stuck in the loop, of can't install the update because "your computer file system verify or repair failed" and no matter what I did I could not get out of this loop. I tried to boot form recover, boot form USB with sierra installer, tried to repair the hard drive which gave me errors like File system check exit code is 8, I tried single user mode, I tried network recovery..... like I said I tried everything. My plan was to dig up the old spinning hard drive to restore an image form it, albeit it few months old but better than nothing. Of course I do not have a backup because I said to myself this is an SSD on a mac what could go wrong, well I learned that lesson. Bottom line what needed to happen was enable journaling of the hard drive, something that was greyed out and was impossible to do. Installing a fresh OS was also not working because the computer would say the drive is locked. Enough of the problem here is the solution.

I bought a thunderbolt cable to connect the iMac to my trusted MacBook Pro. I then installed Disk Warrior software on a MacBook pro. Then I booted the iMac while holding down the t key, which allowed the MacBook to see the iMac as an external drive. Disk Warrior scanned the iMac's hard drive, rebuilt its directory and enabled journaling. I then unmounted the iMac from the MacBook and rebooted the iMac normally, and viola, high Sierra installation proceeded and 40 minutes later I am back to normal. I am considering this post and pay back for all the help I got from searching the net for hours on this issues.

From what I know the drive is locked because somehow it was corrupted. All you need to do is rebuild it using disk warrior which fixed the issue by enabling journaling. I found the mac native disk utility not to be powerful enough to fix this problem, that's why I resorted to Disk Warrior, I am not promoting them and I am not affiliated with them, that is what I used. Let me know if I can be of any help.

I have the same problem.. what do you do if you dont have acces to another mac?

Mine keeps booting to utility disk.

Safe mode/single user mode/recovery/resetting pram dont work

Disk is locked and there are NO enable journaling icon...

Shut the computer down and then Restart.

Start up into Recovery HD and double click the Macintosh HD.

If it asks for, authenticate it.

From: https://discussions.apple.com/thread/5174378

Here’s how the unlock procedure works for Disk Utility:

1. Boot your Mac and hold down ⌘-R (Command –R) to boot from the Recovery HD partition.

2. Open Disk Utility.

3. Select your locked hard drive.

4. Under the File menu, select Unlock “Drive Name”

5. When prompted for a password, enter the password of the authorized account on the drive.

6. Once you unlock the disk, hold down the Option key on your keyboard and click on the File menu.

7. Under the File menu, select Turn Off Encryption… with the Option key held down, it is no longer grayed-out.

8. When prompted for a password, enter the password of the authorized account on the drive.

9. Disk Utility should display a progress window labeled Starting conversion to JHFS+

10. Your drive should now be unlocked.

The drive is failing, or has failed. If you don't already have a current backup, you need to back it up immediately. Do not try repair it or reinstall OS X.

If you live near an Apple Store, make a Genius Bar appointment to have the computer tested. Supposedly there is no charge for testing.

Genius Bar Reservation US

Make a "Genius" appointment at an Apple Store, or go to another authorized service provider.

Back up all data on the internal drive(s) before you hand over your computer to anyone. There are ways to back up a computer that isn't fully functional — ask if you need guidance.

If privacy is a concern, erase the data partition(s) with the option to write zeros* (do this only if you have at least two complete, independent backups, and you know how to restore to an empty drive from any of them.) Don’t erase the recovery partition, if present.

Keeping your confidential data secure during hardware repair

Apple also recommends that you deauthorize a device in the iTunes Store before having it serviced.

*An SSD doesn't need to be zeroed.

You have three options

1. Replace the hard drive
2. Install an external HD and us it as your boot drive
3. Replace the computer

If you are still under warranty of AppleCare Apple will replace the hard drive with a similar drive of the same capacity -- they will not upgrade your HD. If your warranty and AppleCare have expired you can find instructions for replacing the drive yourself at Other World Computing.