FileVault – How Long Does It Take to Decrypt a Hard Drive?

catalinaencryptionfilevaulthard drive

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?

Best Answer

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.

Related Solutions

IMac – Get the UUID from a mostly dead hard drive

Have you tried looking at the kernel log messages? If, as you said earlier, it tried to root from the drive at least once, you can try to find it in the /var/log/system.log, for example:

$ grep 'rooting\ via' /var/log/system.log
Oct 24 18:01:44 localhost kernel[0]: rooting via boot-uuid from /chosen: 4AB3D289-884F-379C-AF7B-************
Oct 25 11:21:57 localhost kernel[0]: rooting via boot-uuid from /chosen: 4AB3D289-884F-379C-AF7B-************
Oct 28 10:30:54 localhost kernel[0]: rooting via boot-uuid from /chosen: 4AB3D289-884F-379C-AF7B-************
...

Those logs are usually kept for months, so you should be able to get it.

IMac – Fusion Drive constantly spinning up and down

There are 2 ways to look what is it doing in sleep.

One is open the Console in utility, then look at the sleep hours log messages.

If you need help with that publish a copy of that segment here in your question.

The second way is using the Terminal in the utility.

In Terminal window type pmset -g

That will show you a list of sleep mode settings and who is preventing the sleep.

Best Answer

Related Solutions

IMac – Get the UUID from a mostly dead hard drive

IMac – Fusion Drive constantly spinning up and down

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