To address this issue that caused problems for folks decrypting from Mavericks’ Recovery HD and Internet Recovery, Apple has made a change to Yosemite’s Recovery HD and Apple Internet Recovery with regards to FileVault 2 decryption. As of 10.10, you can initiate the decryption process from Yosemite’s Recovery HD and Internet Recovery, but the actual decryption will not proceed until you have booted from a drive that is running a regular Yosemite OS install.
When you decrypt from Yosemite’s Recovery HD, you will be notified that decryption is in progress and to run the following command to check on its progress:
diskutil cs list
When checked, you should see output for Conversion Status, Conversion Direction and Conversion Progress similar to what’s shown below:
- Conversion Status: Converting
- Conversion Direction: -none-
- Conversion Progress: -none-
These statuses will not change while you’re booted from Yosemite’s Recovery HD. If you reboot and boot back to Yosemite’s Recovery HD, you should see output for Conversion Status, Conversion Direction and Conversion Progress similar to what’s shown below:
- Conversion Status: Converting
- Conversion Direction: -none-
- Conversion Progress: Paused
Once booted from a regular Yosemite OS install, you should see decryption proceed.
I had filed a bug report about the decryption behavior in Mavericks’s Recovery HD which evolved into a bug report about this behavior. The bug report has been closed by Apple and I’ve posted the bug report at Open Radar now that the Yosemite NDA has been lifted. For those interested, the details are available via the link below:
http://openradar.appspot.com/radar?id=5885738759487488
