Migration Assistant

Being that we deal with Macs on a large scale, we often come across situations where, due to either the need to upgrade to a later generation or their current Mac becoming ill, data needs to be transferred from one machine to another. There are a number of different ways this can be done, but before I get into the details, heres a little disclaimer.

Please Note: The migration or transferal of data from one machine to another is not a fail safe system. OS X’s built in Migration Assistant is designed to transfer data from a different Mac with a maximum backward compatibility of 2x operating systems. It may be possible to extend this further, but it is not advisable because of potential software problems that could be caused. When dealing with older machines running legacy software, it is advisable to either delete the software not compatible with the newer machine, or do a manual transfer instead of using the Migration Assistant to prevent possible problems. Some software faults can depict themselves in a way that appears to be a hardware fault (i.e. flickering screen, jittery curser, loss of bluetooth or wifi, locking up or slowing down, etc), making it difficult to diagnose if you haven’t used the machine before to confirm its hardware stability. Before starting a migration, it is advisable to remove all passwords from accounts on your old machine, as this is one factor that has been seen to repeatedly cause problems from time to time. It is always necessary to disable FileVault on any account being migrated, as no data can be accessed from that account unless it is disabled.

Now that thats out of the way, lets get started with option number one, Migration Assistant:

(The images below are used from a later software version, so if you are running 10.6 or earlier, the windows and text may not look exactly the same, but the process is the same)


Migration Assistant can be accessed in one of two ways. Either through a fresh OS install during the initialisation process (after you select the language you want, it will ask you if you want to transfer any data from another Mac or hard drive) or through an OS with an account created already.

Mavericks Fresh OS

Mavericks Fresh OS

Initialised OS Sample

Initialised OS Sample

Either way, all that is required is for you to connect your old hard drive (in an external enclosure via USB or Firewire), or connect your old mac in target disk mode to your new mac via Firewire, or Thunderbolt. then click ‘transfer’. you can select specific types of data to transfer if you don’t need/want it all transferred, or you don’t have the space for it all on your new computer. simply deselect the options from the list based on what you’d like to transfer as seen below. You can also expand each user account to select specific information within each account.

Select Data

Select Data to copy

If you choose the to use the latter connection type via ‘Target Disk Mode’ instead of with an external drive, then follow these steps to connect your machines together.

If you have an earlier machine, it can only be done via Firewire 400 or Firewire 800. Whereas, if you have a machine from 2011 or later (all except the Mac Pro range), then you can also connect up via Thunderbolt. But the process to initialise Target Disk Mode is the same for both connection types. (please also note, Thunderbolt is different to Mini-Displayport, the latter will not work in this process)

First, ensure your Mac is plugged into the mains if it is a laptop, as the migration process can take a few hours to complete depending on how much data you have to shift across. If you don’t plug in the computer and the battery dies during the process, it will cause corruption on the new machines drive, and it will most likely need to be reformatted before attempting the migration again.















  1. Connect a Male-to-Male Firewire/Thunderbolt cable from one mac to another.
  2. Hold down the letter ‘T’ key on the keyboard of the old Mac and turn it on while still holding the ‘T’ key.
  3. Hold the ‘T’ key until after the machines start up chime occurs and a floating firewire/thunderbolt symbol appears.
  4. Turn on the second Mac and follow the steps above to migrate using the ‘From Another Mac’ option.

Option 2: Clone the entire hard drive

Cloning from one drive to another is another option when upgrading from one machine to another. The upside is that it can be done in a few hours, and if you select a root level clone, it will copy absolutely everything from the old drive onto the new. The downside is that its not failsafe, as it can miss files or partially transfer files, which can cause OS problems or corruption of data. But most applications for cloning will do a comparative check of the data on both drives before finishing the clone to ensure its as accurate as possible.

If using this method, you will need a separate bootable drive (you can boot Macs via external drives. Intel machines via USB or Firewire, or PPC machines via just Firewire), because the application needs to be run from an operating system. I would also recommend running both disk repair and permissions repair on the drive a few times after the clone to help check and clean up any organisation problem with the OS files.

This method is not as straight forward for the average user, so i will not detail the entire process here, but there are many other detailed websites out there with all the details. Typically on a mac, the best free cloning applications are SuperDuper and Carbon Copy Cloner (CCC).

Option 3: Drag and Drop

The third and final option would be to drag and drop data from one hard drive to another.

Target Disk Mode is not only used when migrating data, so you can use the described method above to enter Target Disk Mode on your old hard drive to get the hard drive to mount on the desktop of your new mac to access the folders.

This method is the last of the three suggestions because it can be very difficult for someone not used to the way the data is stored and organised on a hard drive, but it can also cause many problems if the wrong data is copied, or if system folders are deleted or replaced on your new machine. This can cause software problems, or potential locking up of the entire machine if done wrong. Also, many applications have hidden permissions files and folders, as well as different locations for storing data used to make the programme work, so cannot simply be dragged and dropped from one machine to another. Still other applications require authentication when being installed, and can detect when they are copied or moved, and will need re-authenticating when moved from one machine to another.

If you use the ‘Drag and Drop’ approach, i would always suggest installing your applications from their original install disks, then adding your stored files and folders (such as music, documents, media, etc) from your old drive onto the new one so no root folders are being accessed, and you don’t create more work by messing around with the operating system.

I hope you don’t have to use these methods for any other reason than upgrading to a fancy new Mac (if your old mac has died, whether its been run over by a truck, or your housemate accidentally spilled an entire bowl of spaghetti bolognese on your laptop, i’m sorry…)

But i hope this proves helpful when deciding how to get your data from one machine to another. You can also use these approaches when simply upgrading your hard drive capacity on a mac, which is always a good thing.

On another note, because of the construction of a hard drive, its mechanical parts are very fragile. It is very common for them to fail and die, so it is always advisable to keep a backup of all your data. Macs have had a built in tool called ‘Time Machine’,  first available from 10.5 Leopard, which is a great automatic backup tool to remind you to save your important files.

As always, if you have any questions, please let us know and we will do what we can to get an informative response to your question. Macs are our specialty, but amongst our enginerds are many varying hobbies and skills that may come in handy with answering your other questions too.

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5 Responses to Migration Assistant

  1. David Smith says:

    Just (today) took delivery of an iMac and carried out data transfer without apparent problems. BUT (and a big ‘but’) I now have a password on booting up, which we didn’t have on the old Mac and which we don’t know. Any advice, please? Are there any cheats? Or do I have to re-install MACOS and start all over again? All and any suggestions gratefully received.

    • nojboy715 says:

      Hi David. That is something we have encountered with migrations within 10.7 and later unfortunately… Its to do with the user account data being migrated, but the encrypted password is brought over scrambled. This can be a minor glitch, or it could be caused by the apparent unorganised way a FileVaulted drive is locked down. I would always recommend both removing FileVault and removing any account passwords before beginning a migration on drives running 10.7 or later. (passwords can always be added again after its been transferred)
      As you have already encountered this problem, i would suggest one of 2 solutions.
      Firstly, boot onto the ‘recovery’ partition of your hard drive, and within the ‘utilities’ menu, you can sometimes remove an account password. (this doesn’t always work because of the nature of the glitch. this is also OS specific. the option was removed on later operating system, so the option below is the only way forward if you are running 10.10. It can be done through a terminal command on 10.7, 10.8 and 10.9)

      If this fails, i would suggest starting the process over. (erase your new iMacs hard drive and install a fresh OS, then boot your old Mac up and remove all account passwords and disable FileVault, then start the migration process over again)

      Hopefully this will help solve your frustrating problem. It baffled us for a while before we discovered it wasn’t a password being brought over, but rather a scrambled batch of data.
      Good luck.

      • David Smith says:

        Thanks very much for that. In fact, we didn’t have any user passwords on the previous Mac, so even more puzzling! How do I boot into the recovery partition, please? I’ve never done that before.
        Many Thanks,

      • nojboy715 says:

        Then its more than likely a glitch in the migration of some kind. I’m assuming you have attempted to enter the account without a password being typed, correct?

        With the machine turned off, hold down the left ‘Alt’ key when you power the machine up. (keep holding the key down after the audible chime until you see a grey screen with the curser visible)
        This will take you to what is known as the ‘Disk Selection Screen’. You will see your normal hard drive (usually labeled ‘Macintosh HD’) and in 10.7 and later, a second partition called ‘Recovery’.
        Whichever one you click on, it will boot to.
        I hope this helps.

      • David Smith says:

        Thanks very much indeed for your patience and all your help and advice. I eventually re-installed MACOS and reset passwords to nil. Fingers crossed, it seems to be OK . Just a matter of getting printers etc. back now…
        Thanks again to everyone

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