I'm decrypting my hard drive with sudo fdesetup disable (because system Preferences would stop responding when I clicked "Decrypt"), and it doesn't show the progress.

So I left my iMac on sleep mode overnight, and it's still not done. Is it even doing anything or does it just take a while to decrypt a 1TB hard drive?

Also, is there a way to see how long it takes until it's done?

  • I'm pretty sure it won't do it while it's asleep, but idk of any way to show progress.
    – Tetsujin
    Apr 18, 2020 at 9:05
  • @klanomath How do you get to see how long it takes until it's done? It doesn't say in SysPrefs, and entering fdesetup status -extended in a new window just says Volume is APFS. (FileVault Enabled).
    – user371800
    Apr 18, 2020 at 17:00
  • @klanomath The thing is when i enter fdesetup status -extended it just says FileVault is On. Volume is APFS. (FileVault Enabled) and nothing else, not even a percentage.
    – user371800
    Apr 18, 2020 at 17:18
  • @OMN30 Have you started decryption already?
    – klanomath
    Apr 18, 2020 at 17:20
  • @klanomath Yes, it has been decrypting for 24 hours.
    – user371800
    Apr 18, 2020 at 17:21

1 Answer 1


It depends.

There's several factors that go into decrypting a drive:

  • The CPU - how quickly it can "crunch" the numbers to encrypt/decrypt
  • Whether or not your have a T2 chip
  • Drive size - bigger means more things to process
  • Type of drive - SSDs are fairly quick whereas mechanical drives are much, much slower.
  • How it's connected - USB 2.0 (480Mb/s) versus USB 3.0 (5Gb/s) versus SATA II (3Gb/s) versus SATA III (6Gb/s). All these different speeds factor in how quickly the decryption process goes.

When I had to do DoD wipes of mechanical drives, many of them were only 250GB, it could take up to 48 hours and it was just a "3 pass of writing zeros".

So I left my iMac on sleep mode overnight,

When you put your Mac to sleep, it stops the processes. Don't put it to sleep while decrypting.

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