I have an external 2 TB LaCie drive connected via FireWire 800 to my MacBook Pro (8,2 – early 2011 model), which runs OS X 10.8.5. It has one big partition which is a Time Machine target, and the backup is encrypted. My Macintosh HD itself is also encrypted.

Before, I could just plug in the drive and it would automatically mount all the volumes on it, but ever since I've enabled encryption and started a new Time Machine backup, the disk is not mounted automatically anymore – I have to go into Disk Utility and manually unlock it:

Sometimes I even have to enter my master password for that drive.

Of course, that's not really practical: it's a backup drive and therefore should be mounted automatically every time it's plugged in.

I have not changed my /etc/fstab to prevent it from mounting, nor have I changed any configuration regarding mounting or Time Machine. Here's the diskutil list output for the sake of completeness:

   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        *121.3 GB   disk0
   1:                        EFI                         209.7 MB   disk0s1
   2:          Apple_CoreStorage                         120.5 GB   disk0s2
   3:                 Apple_Boot Recovery HD             650.0 MB   disk0s3
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:                  Apple_HFS Macintosh HD           *120.1 GB   disk1
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        *2.0 TB     disk2
   1:                        EFI                         209.7 MB   disk2s1
   2:          Apple_CoreStorage                         2.0 TB     disk2s2
   3:                 Apple_Boot Boot OS X               134.2 MB   disk2s3
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:                  Apple_HFS Data                   *2.0 TB     disk3

How do I get OS X to mount my volume automatically again?

NB: I also noticed that as soon as I eject the drive, it doesn't spin down anymore. It used to do that before though – now I have to shut it down with the hardware switch.

  • I've had a similar problem (still unresolved, despite a completely new computer, keychain wipe, etc) with drives not mounting automatically when plugged in shortly before/after waking the computer up: apple.stackexchange.com/q/121655/1587 Feb 5, 2015 at 2:07

1 Answer 1


I have had the same issue. If you have an entry for the drive in your Keychain, delete it and try again.

To do so, open Applications » Utilities » Keychain Access.app and look for the Encrypted Volume password. Delete it from the list.

Eject and plug in the drive again. When it asks for the master password check the 'remember' button.


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