TweetFollow Us on Twitter

MacEnterprise: Migrating FileVault

Volume Number: 24
Issue Number: 10
Column Tag: MacEnterprise

MacEnterprise: Migrating FileVault

Moving FileVault-encrypted accounts to a new machine

By Greg Neagle,

Another FileVault challenge

A few issues ago, we looked at implementing FileVault in an enterprise environment. FileVault is Apple's technology for securing the contents of a user's home directory. Your organization may wish to protect its users' data on company laptops, in case a laptop is lost or stolen. Using FileVault is one method to accomplish this goal.

In those earlier issues of MacTech, we looked at preparing for FileVault implementation, turning it on for a given user account, and options for managing, automating, and controlling the use of FileVault in your organization. Later, we looked at dealing with some of the day-to-day issues in dealing with FileVault-protected home directories, and methods for recovering from a lost FileVault password.

Moving FileVault Accounts

One thing not covered in the earlier articles is how you might move a FileVault-protected account and home directory from one machine to another. If you are giving a user a new machine, you may need to move his or her existing account and home directory to the new machine. For reasons best known to Apple, the Migration Assistant is of little help in this task - it refuses to migrate a FileVault user unless there are no other users on the target machine. If you have a machine built from a standard image, you may have one or more prebuilt user accounts, like a local administrative account, on the new machine and so the Migration Assistant refuses to move the FileVault-protected user account.

The advice given by the Migration Assistant is to turn off FileVault, move the account, and turn it back on. While this might work, it is problematic for several reasons:

You'll need the user's password, or at least their cooperation, to turn FileVault off. This requires more coordination between you and the user.

You'll need enough available space on the startup disk to make a duplicate of the contents of the user's FileVault-protected home folder. That space may not be available.

Decrypting and re-encrypting the FileVault-protected home directory can take a long time.

If you are using MCX to enforce FileVault, turning it off (and back on) can present a challenge, as the GUI options are disabled.

So it would be better if we could just move the FileVault-protected account as-is. Fortunately, it can be done, and really isn't that difficult - at least if you aren't afraid of the command line.

Basic Concepts

The basic ideas behind moving the FileVault account are simple:

Recreate the account information on the new machine.

Move the FileVault sparseimage or sparsebundle to the new machine.

Edit the account information to point to the FileVault disk image.

Of course, the devil is in the details. So let's get started!

Recreating the account

If you are using mobile accounts, recreating the account is easy. Just create a new mobile account for the user - either graphically, or via the command line. In Tiger, the relevant command-line tool is MCXCacher, located in


You call it like so:

cd /System/Library/CoreServices/
./MCXCacher -U usershortname

which should create a new mobile account for the network user.

For Leopard, the relevant tool is called createmobileaccount. It is located in /System/Library/CoreServices/

It's called like this:

cd /System/Library/CoreServices/
cd Contents/Resources
./createmobileaccount -n usershortname

If you aren't using mobile accounts, you can manually recreate the account using the Accounts preferences pane, or the dscl command-line utility, but be sure the shortname, uid, and GeneratedUID of the recreated account match the original. The dscl utility can be of great help here, allowing you to read the appropriate values from the old account and write them to the new one:

oldmac:/ root# dscl . read /Users/localuser uid
dsAttrTypeNative:uid: 4389
newmac:/ root# dscl . create /Users/localuser uid 4389

Another challenge, if you are not using mobile accounts, is copying the stored password from the old account and machine to the new one, but this, too, can be done. The passwords are stored in /private/var/db/shadow/hash. For local accounts, the shadow files are named after the GeneratedUID of the user account:

root# dscl . read /Users/localuser GeneratedUID
GeneratedUID: 1DECD42B-52EB-4B89-B2B2-359F0623EB1F

So for "localuser" above, the password is stored in /private/var/db/shadow/hash/1DECD42B-52EB-4B89-B2B2-359F0623EB1F. To copy the password hash from the old machine to the new one, you'd just copy that file.

Move the FileVault disk image

The next step is easier. All you need to do is copy the FileVault disk image from the old machine to the new one. But first, let's do some prep work. If you recreated the account on the new machine, you may have a folder in /Users that is partially populated. We don't really need the contents of this folder, as we're going to replace it with the FileVault disk image. If your new machine is running Tiger, or you've recreated a purely local user, just remove all the contents:

newmac:/ root# rm -rf /Users/localuser/*

If your new machine is running Leopard, and you have recreated a mobile account, you should keep the .account directory inside the user's home folder. This stores cached account info and is used by the new External Accounts in Leopard.

newmachine:/ root# ls /Users/mobileuser
.CFUserTextEncoding   Movies
.account                     Music
Desktop                     Pictures
Documents                  Public
Downloads                  Sites

You can remove everything else in the user's folder; just leave .account.

Let's look at the old machine for a second. You might see two relevant directories in /Users:


If you look inside .localuser/, you'll see the sparseimage/sparsebundle. If you look in localuser/, you'll see an .autodiskmounted file. This happens when the FileVault disk image is not unmounted cleanly. The important bit is that you want to find and copy the sparseimage/sparsebundle, even if it's in a different directory than you were expecting.

One strategy to copy the FileVault disk image is to startup the old machine in FireWire target disk mode, connect it to the new machine, and use sudo cp or ditto to copy the sparseimage/sparsebundle. If you do this, it's probably a good idea to uncheck the "Ignore ownership" box in the Get Info window for the FireWire-connected volume. If you don't do this, you can manually reassign ownership of the FileVault image after the copy.

cp -pvr /Volumes/oldmac/Users/myuser/myuser.sparsebundle \ /Users/myuser/myuser.sparsebundle
chown -R myuser /Users/myuser/myuser.sparsebundle

If you cannot abide the command line, it is possible to do this completely from the Finder, but you'll need to first change the permissions and/or ownership of the various directories so you can read and write. Be sure to change ownership and permissions back when you are done copying.

When you are done copying, you should have a username.sparsebundle or username.sparseimage in /Users/username on the new machine. /Users/username and /Users/username/username.sparsebundle should be owned by username, and the owner should have read, write and execute permissions:

chown -R username /Users/username
chmod -R u+rwX  /Users/username

Editing the new account

We're almost there! We've recreated the account, and we've copied the FileVault disk image. But the recreated account has the wrong value for the HomeDirectory attribute. We need to fix that. While previous steps could be done without using the command line, I'm afraid that for this task you have no choice but to fire up the terminal.

newmac:/ root# dscl . read /Users/myuser HomeDirectory   
No such key: HomeDirectory

For a "normal" non-FileVault encrypted home directory, this attribute does not exist (the NFSHomeDirectory attribute does exist, but that's a different thing...) We need to create this attribute and point it to the FileVault disk image.

dscl . create /Users/myuser HomeDirectory '<home_dir><url>file://localhost/Users/myuser/myuser.sparsebundle</url></home_dir>'

The above command should be all one line. Substitute the correct username for "myuser" and in "myuser.sparsebundle". If the encrypted home directory is in the older FileVault format, substitute "sparseimage" for "sparsebundle".

If you did everything right, the user should now be able to log in on their new machine with their username and password and access their FileVault-encyrpted home directory. And maybe you've learned some things about FileVault, mobile accounts and the Directory Service along the way.

Wrapping up

To review:

We recreated the user account on the new machine, using MCXCacher or createmobileaccount if the account was a mobile account; or manually if it was a local account, ensuring the shortname, uid, and GeneratedUIDs matched.

For local accounts, we copied the shadow password file. (Recreating a mobile account generates this for us automatically)

We copied the FileVault disk image from the old machine to the new one.

We edited the local accounts' HomeDirectory attribute to point to the FileVault disk image.

That was a lot of work - but should have been faster than turning FileVault off, moving the account and data, and then turning it back on. Additionally, the user's password was not needed to move the account and data. Once you get this technique down, you might consider writing a script to do most of it for you, which is, of course, what I've done. Better would be to help persuade Apple to update the Migration Assistant to do this: if we can do it, so could the Migration Assistant!

Greg Neagle is a member of the steering committee of the Mac OS X Enterprise Project ( and is a senior systems engineer at a large animation studio. Greg has been working with the Mac since 1984, and with OS X since its release. He can be reached at


Community Search:
MacTech Search:

Software Updates via MacUpdate

Dash 3.4.0 - Instant search and offline...
Dash is an API documentation browser and code snippet manager. Dash helps you store snippets of code, as well as instantly search and browse documentation for almost any API you might use (for a full... Read more
AirRadar 3.1.9 - $9.95
With AirRadar, scanning for wireless networks is now easier and more personalized! It allows you to scan for open networks and tag them as favourites or filter them out. View detailed network... Read more
Printopia 2.1.22 - Share Mac printers wi...
Run Printopia on your Mac to share its printers to any capable iPhone, iPad or iPod Touch. Printopia will also add virtual printers, allowing you to save print-outs to your Mac and send to apps.... Read more
SteerMouse 5.0 - Powerful third-party mo...
SteerMouse is an advanced driver for USB and Bluetooth mice. It also supports Apple Mighty Mouse very well. SteerMouse can assign various functions to buttons that Apple's software does not allow,... Read more
Alarm Clock Pro 10.2.5 - $19.95
Alarm Clock Pro isn't just an ordinary alarm clock. Use it to wake you up in the morning, send and compose e-mails, remind you of appointments, randomize the iTunes selection, control an internet... Read more
Cocktail 10.1 - General maintenance and...
Cocktail is a general purpose utility for macOS that lets you clean, repair and optimize your Mac. It is a powerful digital toolset that helps hundreds of thousands of Mac users around the world get... Read more
RapidWeaver 7.1.7 - Create template-base...
RapidWeaver is a next-generation Web design application to help you easily create professional-looking Web sites in minutes. No knowledge of complex code is required, RapidWeaver will take care of... Read more
MacCleanse 5.1.6 - $29.95
MacCleanse is the product of thousands of hours of intense research and development. It meticulously scans all of the nooks and crannies of a computer for unnecessary junk that can take up huge... Read more
Slack 2.3.0 - Collaborative communicatio...
Slack is a collaborative communication app that simplifies real-time messaging, archiving, and search for modern working teams. Version 2.3.0: Note: Now requires OS X 10.8 or later New The app... Read more
Firefox 49.0.2 - Fast, safe Web browser.
Firefox offers a fast, safe Web browsing experience. Browse quickly, securely, and effortlessly. With its industry-leading features, Firefox is the choice of Web development professionals and casual... Read more

Latest Forum Discussions

See All

4 addictive clicker games like Best Fien...
Clickers are passive games that take advantage of basic human psychology to suck you in, and they're totally unashamed of that. As long as you're aware that this game has been created to take hold of your brain and leave you perfectly content to... | Read more »
Smile Inc. Guide: How not to die on the...
As if Mondays weren't bad enough, at Smile Inc. you have to deal with giant killer donuts, massive hungry staplers, and blasting zones. It's not exactly a happy, thriving work environment. In fact, you'll be lucky to survive the nine to five.... | Read more »
Oh...Sir! The Insult Simulator (Games)
Oh...Sir! The Insult Simulator 1.0 Device: iOS Universal Category: Games Price: $1.99, Version: 1.0 (iTunes) Description: | Read more »
WitchSpring2 (Games)
WitchSpring2 1.27 Device: iOS Universal Category: Games Price: $3.99, Version: 1.27 (iTunes) Description: This is the story of Luna, the Moonlight Witch as she sets out into the world. This is a sequel to Witch Spring. Witch Spring 2... | Read more »
4 popular apps getting a Halloween makeo...
'Tis the season for all things spooky. So much, so, in fact, that even apps are getting into the spirt of things, dressing up in costume and spreading jack o' lanterns all about the place. These updates bring frightening new character skins, scary... | Read more »
Pokémon GO celebrates Halloween with can...
The folks behind Pokémon GO have some exciting things planned for their Halloween celebration, the first in-game event since it launched back in July. Starting October 26 and ending on November 1, trainers will be running into large numbers of... | Read more »
Best Fiends Forever Guide: How to collec...
The fiendship in Seriously's hit Best Fiends has been upgraded this time around in Best Fiends Forever. It’s a fast-paced clicker with lots of color and style--kind of reminiscent of a ‘90s animal mascot game like Crash Bandicoot. The game... | Read more »
5 apps for the budding mixologist
Creating your own cocktails is something of an art form, requiring a knack for unique tastes and devising interesting combinations. It's easy to get started right in your own kitchen, though, even if you're a complete beginner. Try using one of... | Read more »
5 mobile strategy games to try when you...
Strategy enthusiasts everywhere are celebrating the release of Civilization VI this week, and so far everyone seems pretty satisfied with the first full release in the series since 2010. The series has always been about ultra-addictive gameplay... | Read more »
Popclaire talk to us about why The Virus...
Humanity has succumbed to a virus that’s spread throughout the world. Now the dead have risen with a hunger for human flesh, and all that remain are a few survivors. One of those survivors has just called you for help. That’s the plot in POPCLAIRE’... | Read more »

Price Scanner via

Apple refurbished 2015 13-inch MacBook Airs a...
Apple has Certified Refurbished 2015 13″ MacBook Airs available starting at $759. An Apple one-year warranty is included with each MacBook, and shipping is free: - 2015 13″ 1.6GHz/4GB/128GB MacBook... Read more
64GB Apple TV on sale for $159, save $40
Best Buy has the 64GB Apple TV on sale for $40 off MSRP on their online store. Choose free shipping or free local store pickup (if available). Sale price for online orders only, in-store price may... Read more
EyeQue Introduces iOS And Android Based Advan...
Affordable vision technologies developers EyeQue have announced what they claim to be the world’s most advanced intelligent vision solution, pitched as enabling anyone, anywhere to easily and... Read more
Smartwatch Market Tanks, Declining 51.6% in 2...
The worldwide smartwatch market experienced a round of growing pains in the third quarter of 2016 (3Q16), resulting in a year-over-year decline in shipment volumes. According to data from the... Read more
CAZE announces Ultra Thin Glass Screen Protec...
Hong Kong based CAZE has announced its first ultra thin glass screen protector, the Glazz Pro for iPhone 7/7 Plus. Glazz Pro is made from chemically reinforced glass with an anti-fingerprint... Read more
11-inch MacBook Airs on sale for up to $120 o...
Newegg has 11″ MacBook Airs on sale for up to $120 off MSRP. Shipping is free: - 11″ 1.6GHz/128GB MacBook Air: $799.99 $100 off MSRP - 11″ 1.6GHz/256GB MacBook Air: $979 $120 off MSRP Read more
Up to $300 off Macs, $20 off iPads with Apple...
Purchase a new Mac or iPad using Apple’s Education Store and take up to $300 off MSRP. All teachers, students, and staff of any educational institution qualify for the discount. Shipping is free, and... Read more
Apple’s Thursday “Hello Again” Event A Largel...
KGI Securities analyst Ming-Chi Kuo, who has a strong record of Apple hardware prediction accuracy, forecasts in a new note to investors released late last week that a long-overdue redo of the... Read more
12-inch Retina MacBooks on sale for $100 off...
Amazon has 2016 12″ Apple Retina MacBooks on sale for $100 off MSRP. Shipping is free: - 12″ 1.1GHz Silver Retina MacBook: $1199.99 $100 off MSRP - 12″ 1.1GHz Gold Retina MacBook: $1199.99 $100 off... Read more
Save up to $600 with Apple refurbished Mac Pr...
Apple has Certified Refurbished Mac Pros available for up to $600 off the cost of new models. An Apple one-year warranty is included with each Mac Pro, and shipping is free. The following... Read more

Jobs Board

Security Data Analyst - *Apple* Information...
…data sources need to be collected to allow Information Security to better protect Apple employees and customers from a wide range of threats.Act as the subject Read more
*Apple* Retail - Multiple Positions - Apple,...
Job Description: Sales Specialist - Retail Customer Service and Sales Transform Apple Store visitors into loyal Apple customers. When customers enter the store, Read more
*Apple* Solutions Consultant - Apple (United...
# Apple Solutions Consultant Job Number: 52812872 Houston, Texas, United States Posted: Oct. 18, 2016 Weekly Hours: 40.00 **Job Summary** As an Apple Solutions Read more
Lead *Apple* Solutions Consultant - Apple (...
# Lead Apple Solutions Consultant Job Number: 52812906 Houston, Texas, United States Posted: Oct. 18, 2016 Weekly Hours: 40.00 **Job Summary** The Lead ASC is an Read more
*Apple* Retail - Multiple Positions- Towson,...
Job Description: Sales Specialist - Retail Customer Service and Sales Transform Apple Store visitors into loyal Apple customers. When customers enter the store, Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.