how to decrypt external hard drive so it can be re-partitioned

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Level 1

16 points

how to decrypt external hard drive so it can be re-partitioned

I can't repartition an external hard drive which has been encrypted as a time machine backup drive. So I am trying to remove the encryption. But I can't figure out how to decrypt the drive either. I know it is still encrypted since it requires the password when I mount the drive. I have successfuly erased all data at the partition level. But there is no ERASE tab at root level. When I try to re-partition it shows a greyed out "current" and the only thing I can do is to create a 2nd partition the identical size as the first.

I have tried ejecting and remounting. I have tried 2 different macs. Repair disk shows "it appears to be ok". Any suggestions?

Posted on Jun 6, 2013 9:20 PM

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Answer 1

Linc Davis

Level 10

209,547 points

Jun 6, 2013 9:45 PM in response to cwbrandt2

Hard disk bricked after using file vault with time machine

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Answer 2

Jun 6, 2013 11:17 PM in response to cwbrandt2

To do this, follow these steps:

1. Open the OS X Terminal utility and run the following command:

diskutil cs list

The output of this command will look like a hierarchical tree. Locate the long alphanumeric code next to the words "Logical Volume Group" (this code is called a "UUID"), and copy this code to the clipboard by highlighting it and then pressing Command-C.

2. Run the following command to destroy the logical volume group, replacing "UUID" with the alphanumeric string from the first command.

diskutil cs delete UUID

When done this will clear the volume and allow it to be formatted and otherwise customized. See the following screenshot for what this should look like (the two commands are underlined in blue:

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Answer 3

cwbrandt2 Author

Level 1

16 points

Jun 13, 2013 6:08 PM in response to Topher Kessler

Thank you for the detailed instructions. In my search for help I had found other posts suggesting terminal commands. But there were warnings and not enough details for me to feel confortable following them.

Your answer worked and was again proof that the mac community is awesome.

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Answer 4

jinx007

Level 1

0 points

Sep 7, 2013 12:52 PM in response to Topher Kessler

Hi

What happens if it doesn't work? My command says error deleting Corestorage Logical Volume group: Not a valid Corestorage...? I am trying to log into my laptop but it is locked by filevault and i cannot seem to erase or partition the locked disk.

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Answer 5

kingmohd

Level 1

9 points

Oct 25, 2013 6:43 PM in response to cwbrandt2

I encrypt an external hard drive using Carbon Copy Cloner . When I connect that drive to my mac I have to enter the password to unlock it, then I can back up to it.

My question is how can I decrypt that hard drive? Encryption was a simple process of hitting 1 button or so...but there seems to be no "decrypt" button.

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Answer 6

Jan 12, 2014 1:37 AM in response to Topher Kessler

Will this delete all data on the drive? I need to decrpyt so I can resize the partition without deleting my data.

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Answer 7

Jul 21, 2016 5:01 PM in response to cwbrandt2

Use terminal on your Macbook then type in command diskutil cs list, look the volume of your external hard drive that is encrypting and copy it, and type the following.

diskutil cs revert and paste the volume/UUID, If the volume is corect the terminal is asking for your passphrase/password that you use for encryption. Your data is safe, it will only decrypted your external hard drive.

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