Can you help me reformat my disk in recovery mode? Seriously botched Yosemite/FileVault installation

Question

I have a mid-2011 macbook air. When I start up my computer, it automatically goes to recovery mode. I have a backup of my data, so I don't care what I have to do to get OS X working again.

Disk utility shows Macintosh HD, but no partitions below it. When I click verify it tells me to repair the disk. When I click repair the disk, it tells me to repair the disk again... not getting anywhere with this. When I try to reinstall OS X from recovery mode, it does not have my 120 GB partition availible to install on. When I try to recover from my time machine backup, there is no partition to install on.

Here's some context on how I got here: I installed Yosemite this weekend. I elected to use apple's filevault . The encoding process failed. Computer was working alright, but the cooling fans were constantly on and battery was draining quickly. I decided I needed to do something about it. So I tried to recover using time machine in recovery mode and it told me that it failed and that the computer had to be restarted. After it restarted, there was no partition under the Macintosh HD icon in diskutility.

Like I said above, I don't care what kind of reformatting/erasing I have to do, I just want to get my computer out of recovery mode and formatted correctly so that I can eventually recover from my time machine backup that is located on an external hard drive.

Thanks.

Answer 1

So if I understand you correctly, all you want to do is wipe your disk and reinstall OS X.

1. Boot into recovery mode
2. Choose "Utilities" in the Menu bar
3. Select "Disk Utility"
4. Select the disk
5. Click on "Erase" and select "Mac OS Extended (Journaled)"

Then you should be able to do a fresh install of OS X.

Answer 2

You can use the following from Terminal:

diskutil cs list

Find the UUID of the Logical Volume Group for the next command:

diskutil cs delete <UUID of Logical Volume Group>