I tried doing that and got this message: Usage: diskutil eraseVolume format name MountPoint|DiskIdentifier|DeviceNode Completely erase an existing vol

I tried doing that and got this message: Usage: diskutil eraseVolume format name MountPoint|DiskIdentifier|DeviceNode Completely erase an existing volume. Ownership of the affected disk is required. Format is the specific filesystem name you want to erase it as (HFS+, etc.). Name is the (new) volume name (subject to filesystem naming restrictions), or can be specified as %noformat% to skip initialization (newfs). You cannot erase the boot volume. Example: diskutil eraseVolume JHFS+ UntitledHFS /Volumes/SomeDisk Edit: I got it to work by doing hdiutil attach -nomount ram://1165430 on one line, then diskutil eraseVolume on the newly mounted volume.