Reformatting Hard Drive, help please (without recovery disk)

[Sparky2012]

So I have done this before on my iMac but I am trying to help my sister do it as she is having several issues with her Macbook Pro 2011.

What you do is you hold Cmd + R until the Apple Logo appears. Then click Disk Utility and then on the left, click the Macintosh HD Volume and click Erase, name the volume and the format OS X Extended (Journaled), and finally hit Erase. Wait a while for it to erase and then back out of Disk Utility and then click on Reinstall OS X and again wait a while.

The part I'm having trouble with is when my sister goes into Disk Utility to erase the Macintosh HD volume, its greyed out and I have no idea why or how to fix it. Help would be much appreciated!

 

[Weaselboy]

While you are in that same recovery screen open Terminal app from the Utilities menu and run each of the commands below then post the results back here so we can take a look. These commands will show the volume layout of the disk.

diskutil list

diskutil cs list

 

[Sparky2012]

Sorry for the delay. Heres the results:

 

[Weaselboy]

Sorry for the delay. Heres the results:

Okay... it is not letting you remove that volume because it is encrypted with FileVault. Do this... back in that same recovery screen go back to Terminal and enter the command below. That will wipe the encrypted volume, then you can go back to Disk Utility and in the erase tab format the entire disk like you mentioned earlier.

diskutil cs delete "Macintosh HD"

Make sure you do the command exactly like this including the quotes.

Edit: Fixed command typo.

 

[Sparky2012]

Okay... it is not letting you remove that volume because it is encrypted with FileVault. Do this... back in that same recovery screen go back to Terminal and enter the command below. That will wipe the encrypted volume, then you can go back to Disk Utility and in the erase tab format the entire disk like you mentioned earlier.

diskutill cs delete "Macintosh HD"

Make sure you do the command exactly like this including the quotes.

Sorry for sounding paranoid but the part of the command you gave me "diskutill" is that meant to have 2 l's as other commands you gave me only had one l ?

 

[Weaselboy]

Sorry for sounding paranoid but the part of the command you gave me "diskutill" is that meant to have 2 l's as other commands you gave me only had one l ?

One l (el) only... typo on my part. Sorry about that.

 

[Sparky2012]

One l (el) only... typo on my part. Sorry about that.

No problem. I asked my sister to attempt to turn FileVault off and so might not have to do any of this terminal stuff. I'll keep you posted.

 

[Weaselboy]

No problem. I asked my sister to attempt to turn FileVault off and so might not have to do any of this terminal stuff. I'll keep you posted.

If you don't want any data on there, it is much much faster to just run this command from recovery. It will clear off that volume in about five seconds. It may take hours to unencrypt the FV volume.

 

[Sparky2012]

If you don't want any data on there, it is much much faster to just run this command from recovery. It will clear off that volume in about five seconds. It may take hours to unencrypt the FV volume.

DAMMMNNN, oh well its gonna take about 6 hours apparently... wish I had read your post first haha. Cheers, I'll keep you updated.

 

[Weaselboy]

DAMMMNNN, oh well its gonna take about 6 hours apparently... wish I had read your post first haha. Cheers, I'll keep you updated.

You should be able to just reboot and interrupt it then run the command from recovery.

 

[Sparky2012]

You should be able to just reboot and interrupt it then run the command from recovery.

Sister doesn't want to interrupt it now just in case... oh well.

 

[Weaselboy]

Sister doesn't want to interrupt it now just in case... oh well.

Daw... big scaredy cat!

 

[Sparky2012]

Daw... big scaredy cat!

Lol! She says thanks for the help so far.

 

[Weaselboy]

Lol! She says thanks for the help so far.

You bet... once it decrpyts and you go back to recovery you will be able to erase with Disk Util no problem.

 

[Sparky2012]

Just an update. The decryption finished and as you said, we could then wipe the Macintosh HD volume. We did so and reinstalled OS X after backing out of Disk Utility. Everything went smoothly and the MacBook Pro is running well again. Cheers for your help again!