I recently attempted to enable FileVault on macOS Sierra. I clicked the restart button, but on reboot rather than starting to encrypt the disk it simply displayed the prohibited sign. Now I can't boot to my Sierra drive in single-user mode either.

My Recovery paritions (one for Sierra and one from an older El Capitan install whose main partition no longer exists) are both displaying the same issue, no booting to recovery in general or in safe mode. I need help, I had a lot of code store on the Sierra partition, but I never made backups of some of it, and the backups I have are several weeks old. I don't have the recovery key, it is in a file on the now dysfunctional recovery disk, so I need to know, is there any way to salvage the install from a macOS install usb?

If so is Mavericks a new enough version to do so from? Can I simply decrypt my Sierra partition from inside of it or would I require at least a Sierra installer to do so, and if I can't decrypt it from an installer, would it be safe to install Mavericks over Sierra, or to a different disk, extract my personal/company projects from it and simply re-upgrade once I had it working again in general. Again I need help, and I would rather not have to wipe and lose all of that data.

UPDATE: It seems the Mavericks installer can't load drivers on boot, and I don't know of another way to access the filesystem. If it turned out the disk didn't get encrypted would it be possible to boot a live copy of linux, mount the disk and disable FileVault from there? If so how would I disable FileVault?

  • 1
    Please boot to Internet Recovery Mode (or an installer thumb drive/ full os x thumb/drive) or attached as Target Mode disk to a second Mac, open Terminal.app, enter diskutil list, diskutil cs list and sudo gpt -r show disk0 (or maybe disk1, disk2 - it depends how you boot/attach the Mac) and add the result to your question. I prefer text but you may also take pics and post the pics. If you have more than 2 pics post additional pic links to the comments and I'll add them. With one rep point you are only allowed to publish two links (1 pic counted as 1 link) in the question's body .
    – klanomath
    Oct 26, 2016 at 0:44
  • Well, I figured out that apparently the bootloader can't find the kernel. A fairly big problem as well is that I use clover UEFI (I dual booted windows and it was just easier than boot-camp.) However this means I cannot use key-combos on boot, I have to use boot arguments. Is there a boot argument I can use to get into internet recovery mode? All I can find is references to the key-combo. Oct 26, 2016 at 0:49
  • Do you have a bootable OS X installer thumb drive or a 2nd Mac? Hmm Clover means it's a Hackintosh?
    – klanomath
    Oct 26, 2016 at 0:51
  • Booting to IRM should be pre-Clover-EFI code. You can boot to IRM with a completely empty unformatted disk. You may have to reset SMC/NVRAM though.
    – klanomath
    Oct 26, 2016 at 1:01
  • No, not a Hackintosh, Customac, didn't have space for an iMac's all encompasing monitor so I took spare parts from a handful of compatible iMacs and frankensteined them in a tower case. I have a second Intel Mac, but it's a 32-bit MacBook Pro so I doubt it would be compatible with target-disk mode on my main machine. I also have a Mavericks install-usb I made a while back, and a Snow Leopard 10.6.3 DVD, nothing newer though. Also didn't realize IRM was part of the UEFI, will try now. Oct 26, 2016 at 1:03

1 Answer 1


First if all, thanks to @klanomath or I likely would still be assuming the wrong issue. He was correct that the data was never actually encrypted due to FileVault's incompatibility with CloverUEFI. I used a Mavericks install USB, and used Terminal from inside it to confirm that the data was not encrypted, followed by using the "Turn Off Encryption..." option for the disk in disk utility, and immediately rebooting after double checking that the disk was not actually actively decrypting.

I now have access to my Sierra install again, and will shortly test my Sierra and El Capitan recovery partitions to see if they are working.

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