OS X Mountain Lion and Disk Encryption Failed: How to delete encrypted volume
If you have a encrypted volume created by FileVault or FileVault2 and you are doing a clean installation of Mountain Lion OS X in Disk Utility, maybe you can receive a
“Disk Encryption Failed. Disk Encryption failed with the error: There is not enough free space in the Core Storage Logical Volume Group for this operation bla bla bla”
message when you try to delete the volume.
When you click the “OK” button, the volume is magically hidden so only the physical volume is shown.
Don’t panic, exit from Disk Utility, open the terminal and digit:
diskutil cs list
It will show a list of CoreStorage (or rather encrypted) volumes.
Well, copy the UUID characters of the Logical Volume and digit:
diskutil cs delete THECOPIEDUUID
Replace THECOPIEDUUID word with the UUID characters just copied.
It will destroy the logical volume group and erase initialize and mount the disk.
Now quit terminal, go back to Disk Utility and enjoy yourself!!