I use /etc/fstab to mount a few external volumes at boot time (using a UUID= line). That makes them available at boot before anyone is logged in and thus they can be used for certain services.

This is easy enough and it works. It is also essential because there is no way to let LaunchDaemons wait until disk arbitration is up and running for volumes mounted in /Volumes. It also enables Time Machine to operate continuously, also when nobody is logged in. Which is very useful for a 'server' Mac (e.g. running Server.app for Open Directory and other open source services).

What I haven't done yet is try to do this with an encrypted volume. I was wondering if there is a way to have the external volume encrypted and still mount it before anyone is logged in.

The machine is a late 2018 Mac mini. It has a T2 chip so maybe I can use the security commands to tell the Mac about the credentials for the external volume.

I am using macOS Mojave but expect to be upgrading to Catalina.

  • Have you tried storing the volume password in the System keychain (see this answer to a related question)? Jan 21, 2020 at 23:47
  • Please mention your version of macOS - there have been issues with some minor updates which then get fixed later.
    – Gilby
    Jan 22, 2020 at 5:19
  • You can use this free script from jridgewell @github, I currently am using it since Mojave and now on Catalina. Works perfectly because it creates a service which is run on the boot [via launchd, before graphical interface] and mounts the encrypted drives using the password stored the system keychain. github.com/jridgewell/unlock
    – Prado
    Jan 22, 2020 at 10:28


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