Deleting a hard drive protected by password with Mac OS X Yosemite I recently changed my hard drive for a SSD device. The removed storage device can be used as an external drive, via USB. I want to delete everything on this HD, but it is asking me for a password when I plug it in the Mac. I forgot the password.

I tried every password I have in mind, but it didn't work. I want to force format of the hard drive, but neither Disk Utility nor Terminal commands works (Apple may have locked these functions). 

I tried the procedures described in this topic, without any success. 

With Mac OS Yosemite 10.10, the following message is displayed in Terminal:

Usage: diskutil coreStorage delete lvgUUID|lvgName

Delete a CoreStorage logical volume group. All logical volumes will be removed.
Ownership of the affected disks is required.


Is there a way to overpass this with Mac OS X?
If a partition was encrypted with FileVault, and you have forgotten your password, you need to boot into the Recovery Partition to format the partition / drive. (Hold down Command+R during startup to get there.)  From there, you can use Disk Utility to erase the encrypted partition.