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I have accidentally given my external Extended journaled hard drive (with password) the command to "decrypt" the disk.

When you restart the decryption starts immediately on the external, how can you stop it? (even via a command line option in terminal.app or such)

bmike
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HHermano
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    I'm fairly certain this is not possible. Since there are a couple possible encryption options - would you consider adding a diskutil list (and cs list / apfs list trimmed to the en/decryption progress) and what sw_vers shows for your build and version? – bmike Jun 19 '19 at 11:22
  • Yours seems to be the reverse as this - and some cancel function would presumably pause the decryption and then re-encrypt anything that's so far processed. https://apple.stackexchange.com/questions/353174/why-there-is-no-cancelling-mechanism-for-filevault – bmike Jun 19 '19 at 11:25
  • The output from diskutil cs list <GUID> shows "Revertible: No" for my backward encryption. This appears to confirm the other comments and answers here. It seems unlikely that a long-distant future OS might one day show "Revertible: Yes" but by then my (very slow) decryption and re-encryption will have completed. – Mic Channel Sep 14 '20 at 11:34

1 Answers1

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It is not possible to stop the decryption of the drive while also using the drive.

You can unmount and possibly unplug the external drive, and the decryption will obviously stop.

However, as soon as you plug the drive in again and mount the file system, the decryption process will continue. You cannot ask the system to stop that.

Your options are either to a) let the decryption process finish, and then apply encryption again -- or b) backup the files off the drive, wipe the drive, create a new encrypted file system and copy back your files.

Option (b) usually takes just as long as option (a), but requires a lot more manuals steps. So I would recommend option (a).

jksoegaard
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