Moving to a new Mac: planned, or pushed

A new Mac – particularly at this time of year – can be an unexpected surprise, or an unplanned necessity when your current Mac suddenly becomes unreliable, or fails. Either way, it is important to plan ahead, so that getting that new Mac up and running is swift, and as painless as possible.

If your old Mac has little on it which you need to move across, you have but a single mail account, and your computer doings are small and simple, then you may not need to do much at all. By the time that you have worked your way through configuring the new Mac, you may just need to copy across a few folders, and off you go. I am envious of such simplicity.

The truth for most users, particularly when you have had a succession of Macs going back to early versions of OS X or even long before, is very different. You have some important information – your Contacts address book, calendars, and a bit more, perhaps – shared in iCloud, loads of apps purchased from the Mac App Store, and many not, iTunes syncs of your iPad and iPhone, and a tangled web of folders in Documents. In my case, well over 150,000 items totalling towards 750 GB.

However you tackle that, it is not likely to be quick, so you need to prepare options which will minimise the time and effort involved. You should also try to have a fallback method which is completely robust, in the event that your first choice does not work as you expect.

The vehicle

The more complex and sizeable your task, the more likely you are to find Migration Assistant the best means of accomplishing it.


If it has been a while since you last used Migration Assistant, then you should make yourself aware of how it has changed. When transferring between two Macs, it works most seamlessly when you run it on both, as a server (on the old Mac) and client (on the new one). If the old Mac is past starting up normally, then you will need to mount it (or a copy of its hard disk) on your new Mac for the migration process. If you want to migrate from a Time Machine backup, then that will need to be mounted on the new Mac.

The fastest route possible

The means of connecting the old files with the new Mac then determines how quickly migration can be accomplished. First preference – if you ignore exotic options such as fibre channel connections – must now be Thunderbolt, which is well supported by all recent Macs, and quicker than almost anything else available.

It is not always as simple as it should be, though. New Macs ship with Thunderbolt 2, which is electrically (and in most other ways) identical to Thunderbolt 1 on older models. But you can still hit problems, with suspect cables, or undocumented quirks. When I tried to mount my old iMac in Thunderbolt Target mode on my new iMac, the latter was unable to see it, even though the old iMac mounts fine on a MacBook Air, for example. Always expect the unexpected!

migration2If your old Mac is too old to come equipped with Thunderbolt, prefer FireWire 800 over USB 2, and – unless you know that you can get real Gigabit Ethernet transfer speeds – prefer those over wired network connections. When you can only use USB 2 or WiFi, then I am afraid that migration is going to be long and painfully slow.

Migration Assistant will happily work from a live Mac, a mounted drive, or a Time Machine backup, but will be quickest if the contents are plain (rather than linked in the way that Time Machine uses) and the files defragmented. If you have the chance to make a defragmented copy of the original drive using a utility such as Carbon Copy Cloner, that will be quickest, as Migration Assistant copies each file at a time. But making that initial copy also takes time, so you may not be any better off, unless you want the added safety of that mirror copy too.

My migration plan was to run Migration Assistant on the mounted drive of my old iMac. My fallback was to hook up the Promise RAID on which I kept its Time Machine backups, and that turned out to be the successful option.

Preparing to move

If your old Mac is still running in fine fettle, you should prepare it for migration. Make a full Time Machine backup, and make a mirror copy of its hard drive for added safety if you wish. If you are going to use a Time Machine backup, make sure that you have not excluded important folders from that backup: open the Time Machine pane and check carefully. Also browse the log of that last, critical backup, using Console, to ensure that there were no errors. There is nothing worse than relying on a backup which failed.

You should also make separate copies, either before or after migration, of your most vital files and folders. Those which I always include are:

  • all user keychains stored in ~/Library/Keychains; you can copy those across after migration and refer back to them (remember the password required to unlock them) if you seem to have lost logon or password information anywhere;
  • the latest copy of the mail database for each mail client app, particularly any third-party apps;
  • all work in progress;
  • any other important folders or files which you cannot afford to lose.

These can conveniently go onto an external hard drive, perhaps.

If you have apps which have to be de-authorised on the old Mac in order to authorise them on the new one, remember to do that immediately before the migration process. Additionally, in iTunes or its web pages, open your iTunes account details and check that you still have sufficient scope to authorise your new Mac. If you have five Macs already authorised to play iTunes protected content, de-authorise them all, then authorise each Mac afresh, as you need.

You should already have two-step authentication enabled on your Apple ID and its associated accounts. When you start configuring your new Mac and migrating to it, this will be used on several occasions. Ensure that the iPhone or other ‘master’ device for this is turned on and connected, so that you can read off the four-digit codes, etc., to complete each step.

Making your move

When your new Mac arrives, and before you power it up for the first time, set up your preferred migration connection. If you are using your old Mac in a Target configuration, connect it up ready, ensure it is properly hooked up to your new Mac, then start the old Mac up with the T key held (preferably on a wired USB keyboard) until the Target icon appears on the display. Then start your new Mac up, and – if you can – go straight into the migration process.

If that fails, for instance your new Mac cannot find the source for migration, press on with configuration. You can shut the migration source down, and return to that task later.

Many new Macs do not ship with the very latest release of OS X: my iMac, for instance, came with 10.11.0 pre-installed. If you do not migrate during first configuration, open the App Store app, download, and install updates, particularly those for OS X, as they are likely to lead to more robust migration. Then, when your new Mac has been configured and updated and your old Mac is hooked up and ready, open /Applications/Utilities, and run Migration Assistant.


After the move

Once migration is complete, you will need to check all your apps, particularly those which require any form of authorisation or serial numbers, and work through email connections and accounts, and everything else which you need to use. Don’t get rid of your old Mac until you are entirely happy that your new one is working fine, and that you have a full backup from it.

I always try to keep a complete image copy of my previous Mac’s hard drive, perhaps mounted in a USB 3 case, so that I can look back if I cannot find a document or app on the new Mac. If you are able to, keep the entire Time Machine backups for the old Mac, which should cover every eventuality.

If you intend passing your old Mac on to someone else, or sending it for recycling, you will then need to prepare it for those, as I have detailed here.