The Mac user's guide to Time Machine

14th Mar 2010 | 08:00

The Mac user's guide to Time Machine

How to keep files safe and what to do when the worst happens

Introducing Time Machine

Your Mac is in all probability one of your more prized possessions. Perhaps you even have more than one – a desktop and a portable, and an iPod touch or an iPhone to complete the line-up.

What's easy to forget though is that the kit itself is only part of the story. It's actually your data that's really valuable. If your Mac breaks down, it can be repaired. But if a hard drive croaks or something is accidentally deleted and it hasn't been backed up, there's no way to ever recover it.

For most people, their Mac stores all their data, from bank account information to photo libraries, home movies and email correspondence. It's fair to say that for many users, their entire life is on their Mac. And yet backing up is sometimes thought of as an inconvenience and something that people only start to do after they've already lost some important files.

Since OS X 10.5 Leopard, Apple has offered Time Machine, a straightforward and hassle-free backup utility integrated into the system. It's so easy to use that there's no excuse not to be using it regularly.

We'll show you how it works, how to get the most out of it and how to restore deleted files, folders and even entire systems – plus, of course, the various online backup and other archiving tools on offer. With our guide to backing up, you need never lose anything again…

Introducing Time Machine

Mac OS X 10.6 is the most stable and powerful operating system that Apple has ever created, but that doesn't mean that nothing will ever go wrong with your files. An accident, a theft, or mistakenly deleting or overwriting a file or folder can all result in the loss of important data.

And that's not even counting the possibility of a hard drive failure or the unexpected disconnection of an external hard drive, either of which can in some cases be terminal.

With all the focus on using your Mac as the hub of your digital life, it's easy to forget that storing everything on a single machine is a great idea – unless something goes wrong with that machine.

Time machine drive

With OS X 10.5, Apple introduced Time Machine, an outwardly simple and straightforward backup tool tightly integrated into the system. It was a typically Apple-like approach to nudging users towards a certain way of working – in this case, backing up. There are no complicated options, no fiddling and best of all, it works automatically.

You'll find Time Machine in your Mac's System Preferences if you're running OS X 10.5 or 10.6, with a large, friendly on/off button to activate or deactivate it. It works by initially making a byte-forbyte copy of your system to a secondary or external hard drive, including not just all your data and applications but also the system itself.

Every subsequent backup that you perform or that is done automatically is incremental, meaning Time Machine only backs up files that have been added or modified since the last backup. It's able to determine this information thanks to some complex low-level technology using something called 'fsevents', though all most users need to know about this is that it works invisibly in the background.

The great advantage of incremental backups is that they use far less space than just copying everything every time. It also means you can rest assured that every new or modified file is being backed up, without you having to know what or where those files are. r

Recovery operation

Time Machine would be merely a good solution if this was the whole story, but the reason it's special is that it lets you recover data in a really intuitive way. By entering Time Machine's 'history' view, your Mac can display snapshots of every file and folder at every point it has been backed up.

So, for example, if you have deleted or changed an item, you can go back to the last backup and locate it from the point before you changed it; or, from the point before that, for as many backups as you have. From there you can restore the file or delete it from the backup, if you wish.

You can use Spotlight to preview an item to see if it's the one you want, and navigate back and forth through a folder's history.

Big fast backups

It makes sense to back up to an external FireWire or USB2 hard drive, as these are both surprisingly inexpensive and huge in size, though network drives and partitioned internal drives are also supported in some configurations. For as long as the specified drive is connected and Time Machine is switched on, it will keep hourly backups for the past 24 hours, daily backups for the past month and weekly backups for previous months.

If you prefer, you can alter this schedule with a free app called Time Machine Scheduler. You might want to do this if you worry that an automatic backup starting up could interfere with your work or slow your Mac down. You can increase the backup interval and also force it to skip backups between specified times of day, but still leave it activated so you don't have to keep turning it on and off.


There's not much point in getting a backup drive that's the same size as your hard drive, as it will probably fill up quite quickly, especially if you regularly add or modify lots of large files. The good news is that very large drives are now commonplace and so a 500GB, 750GB or even 1 terabyte external hard drive shouldn't break the bank.

Western Digital's 1TB My Book Essential can be picked up for around £75, and LaCie's 2TB Neil Poulton Design drive is around £150. If your needs are more modest, LaCie makes a 500GB 2.5 inch drive for around £70.

Apple of course makes the Time Capsule, a combined 802.11n wireless base station and 1 or 2 terabyte hard drive specially designed to work with Time Machine and offering wireless backups, so you don't have to manually connect a drive to one or more Macs to back them up.

Although it's more expensive than a basic drive, it does offer various other advantages such as dual band Wi-Fi, guest networking, wireless drive sharing and wireless printer sharing.

With regular backups comes the probability that a drive will eventually fill up, but there are things you can do to prolong the amount of time before this happens. Namely, excluding some items from backups.

Obviously you want your important data to be backed up regularly, and leaving Time Machine switched on and the drive connected is the most sensible way to achieve this. But there are situations where backing up certain files is unnecessary and will just eat up space.

For example, if you are temporarily storing large files on a drive before moving them somewhere else, you may not want them included in your hourly backups. Similarly, if you have a Final Cut scratch folder for storing temporary video files, backing this up could be undesirable.

The solution is to exclude them from Time Machine's schedule by clicking Options in Time Machine and adding the relevant folders to the list of excluded items. If you decide you do want them to be included, you can remove them from this list, even if it's only temporarily so they get backed up once a month, for example.

Restoring backed-up data

Recovering files from Time Machine is easier than you think…

Backing up lots of files is relatively easy, and finding individual files that you want to restore is almost as simple. Time Machine's great strength lies not only in the fact that it's easy to use and works incrementally, only backing up files that have been added or changed since the last backup, but in the way that it provides access to those backups.

With more basic software, you usually have to pick your way through an arcane set of options to look for the items you're after. With Time Machine however, you can navigate in a much more intuitive way.

There are many possible situations in which you might want to get hold of an earlier version of a file or folder. The most obvious would be when you have accidentally or deliberately deleted something but then later find that you need it back; or, where you have changed a file but then realise you want to get that original version back again.

With Time Machine you're able to access a file or folder at every point at which it's been backed up. And since the backups are incremental, it will only have been backed up when it has been modified in the period between two backups. So provided that you let Time Machine run regularly, you should be able to access items as far back as their creation or first backup.

By choosing to enter Time Machine from the menu bar icon, which you can choose to show in Time Machine's preferences, you will invoke the Time Machine interface. This causes the Desktop to slide away and be replaced with a screen depicting the various stages of the currently selected folder going back through time.

Along the right-hand side of the screen you will see a timeline stretching from the present back to the first backup, complete with dates, and two arrows to navigate back and forth in time. If you run the mouse over this timeline you will see that it behaves a little like the Dock, magnifying itself to reveal more details about the time period you have selected and displaying specific dates for any backups that you mouse over.

Click on one of these to jump straight to it. A bar along the bottom of the screen shows you the exact date and time of whatever backup of a folder you are looking at.

To use Spotlight within Time Machine, you can type a search term into the search field in a Finder window and hit the back arrow to make Time Machine search through its backups for that term. If you don't know exactly when you last deleted or changed a file, you can use the back arrow to automatically travel through time to see when that folder was last modified.

Once you have located an item, you can use Quick Look by selecting it and hitting [Spacebar] to get a preview of its contents. You can't open items directly in Time Machine view, but you can preview them by using this method. In the case of music and movies, Quick Look will actually let you play them back.


Once you've identified an item you want, you can restore it by selecting it and pressing the Restore button at the bottom right. The file will then be copied to the Desktop or the current instance of the same folder it's located in, if it still exists. If two items in the same folder are going to have the same name, you're prompted to keep only one or both.

In OS X 10.6 you can right click on an item in Time Machine view and choose Restore to… which will let you choose a destination. For users of OS X 10.5, make sure the 'action' or 'gear' icon is present in your Finder window's toolbar. You can enable this by choosing View > Customize Toolbar.

This contains an option called Restore to which has the same effect. The item will remain as part of the backup, but now will also exist in the present, and so will be included in the next backup.

It's possible to restore several items or several folders within a folder by simply multiple-selecting them, holding the Shift or Command keys while clicking to choose them.

The right-click menu for one or more items in Time Machine also has some other functions. There's Open, which activates Quick Look, Get Info to reveal item information, and some deletion options.

Delete Backup will remove that instance of that item from the currently selected backup, and Delete all backups of the file will identify any instances of that file that exist in any of the backups on that drive. This is useful for saving space when big items are using it up and are no longer required.

Restore within Apple apps

Time Machine also works within some Apple apps Being able to recover files and folders is great, but many applications store their information in different ways than simply files with names in the Finder.

Applications like Address Book, Mail and iPhoto, for example, use databases of information and it's not so straightforward to pull a single email, contact or photo out of a backup like you could with a folder or a Word document, because they're contained within a larger database.

Luckily though, Apple, having designed all of the software in question, has addressed this and made it possible to access certain restore features of Time Machine from within these applications. Although you could navigate to the database files using the regular Time Machine view, this method isn't actually all that helpful because it wouldn't show you the information in any kind of usable form.

And by restoring that information to the desktop you would still have to open it in the relevant application to view it, which can cause problems with overwriting current data.

The solution is really quite simple and involves booting the relevant application and then, with it still in the foreground, invoking Time Machine either from the Dock or the menu bar.

What happens then is that Time Machine's interface appears, only instead of showing the Finder and its windows as normal, it shows the application's window. You can then move back and forth through time and for each backup you will see the relevant data that existed in that application, at that point.

So in Address Book, for example, even if you have deleted some contacts, you will be able to go back in time while staying within Address Book's interface and restore one or more contacts back to the present. In Mail, you can do the same and restore mailboxes or individual email messages that you had since deleted.

Time Machine will avoid duplicating mails by creating a separate mailbox within Mail for the recovered emails. In iPhoto '08 or later, you can do the same and restore photos from previous backups. Even GarageBand from version '08 onwards now supports Time Machine, so if you open a GarageBand project and invoke Time Machine you will be able to revert to an earlier version of a project, as long as it was backed up.

There are a couple of caveats to this, even though on the whole it's very useful. The first is that you cannot restore these things to an alternative location like you can with files and folders; they have to be restored to the current database folder of the application in question. As such, in some cases they may overwrite current data, unless you keep your eyes open.

The solution to this in GarageBand is to duplicate the current project file prior to restoring an older one, so that you have a copy of both.

As we have noted, Mail creates a separate mailbox to avoid confusion. iPhoto will prompt you to overwrite any images that are identical to the ones you're restoring and so gives you the choice whether to do so or not. Address Book will ask if you want to add the selected cards to the database and will warn you if the card is a duplicate of an existing one, giving you the option to review the conflicting information and amend it if necessary.

So as long as you understand what you're restoring, there should be no problems with overwriting existing data.

Another minor quirk of this way of working with Time Machine as opposed to the regular files and folders approach is that sometimes, if you enter Time Machine with an item selected that wasn't present or was excluded when some of the backups were done, those backups will be greyed out in the timeline on the right and you won't be able to select them.

If for example you have recently created a mailbox in Mail and then enter Time Machine with that mailbox selected in Mail, only backups made since that mailbox was created will appear in white as normal; the earlier ones will be greyed out.

You should, however, be able to return to Mail and select another, older mailbox and then back in Time Machine view, the previous backups associated with that mailbox will be available to select.

Other applications do not at present integrate with Time Machine in this way, so if you enter Time Machine with another application in the foreground, it will simply slide from view and the regular Finder view will take its place.

Time Machine integration with these key Apple applications might seem like nothing too exciting on the face of it, but in fact it's incredibly useful. You have always been able to back up a load of information in one go – your Mail database or photo library, for example – and then dig through them in the Finder later to try to locate and extract individual mails, pictures, contacts and so on.

But that can be a long and slow process, especially compared to the convenience of simply jumping into Time Machine within an application and being able to search all its backed up data in the same view you normally see when using the application. All the formatting remains intact and of course you can use Spotlight from within Time Machine to search.

In fact, Address Book, Mail and iPhoto all have their own search fields that still work in Time Machine view, so you can quickly search any backups directly from inside the app, making it easy to find data from even the biggest library of mail, pictures or contacts.

At present, these are the apps that integrate with Time Machine, but hopefully Apple will in future add this level of backup support to other apps.

Other backup solutions

Time Machine isn't the only solution for backing up your Mac…

Time Machine is certainly easy to use and for many users running OS X 10.5 and 10.6, it's a great solution. There are others, however, for whom alternatives might be better, or at least for whom other backup tools could be used in conjunction with Time Machine for added security and flexibility.

At its most basic, of course, backing up a Home directory (for example) is as simple as dragging and dropping the folder onto an external hard drive; or, burning data to rewritable or one-shot DVDs. Although this is OK, its reliant on you to remember to do it and doesn't provide any file recovery features that are more advanced than what the Finder has to offer. It certainly can't provide a bootable backup, since OS X uses so many invisible system files with special permissions.

So a more dedicated solution is preferable. One drawback of Time Machine is that it doesn't make bootable backups, and so in an emergency all you can do is restore it to a hard drive.

Some other applications, though, do enable you to make bootable backups, which you can then boot from an external drive on other Macs for the purposes of troubleshooting or testing systems. One such application is SuperDuper! ($27.95).

This deceptively simple program is actually very powerful and works on PPC and Intel Macs on OS X 10.4 and 10.5 right up to the latest version of 10.6, which is of course Intel-only. As well as scheduling, it also supports 'smart updating', which is essentially similar to the incremental features of Time Machine.

Crucially, backups made with SuperDuper! are bootable, so you can store a fully bootable backup as well as a Time Machine backup and boot from it in the event of a problem.

Carbon Copy Cloner, free donationware, also supports scheduling, incremental backups, backing up over a network and of course bootable backups. It's also simple to use and will provide you with a fully working clone of your system that can be booted from an external drive, should you run into difficulties.

Carbon copy cloner

Users with older Macs as well as MobileMe subscribers might want to look at Apple's own venerable Backup application, although since it was superseded by Time Machine, OS X 10.6 doesn't appear to be officially supported. That said, it seemed to work fine on our 10.6 MacBook.

Other low cost or free backup applications include iBackup (free) which supports multiple sets of backups, scheduling, networked backups and smart folders; and also Synkbackup, which comes in various paid-for versions.

The reason it's so important to have a bootable backup of your OS X system is that in the event of a major problem, troubleshooting and first aid is far easier if you can boot a Mac from a working system.

Booting from an OS X install DVD is fine for certain tasks but won't give you much access to the system. Booted from the DVD, you can run hardware checks on the Mac's internal hard drive, erase and reinstall the system and restore a Time Machine backup, amongst a few other things. But these latter two are quite drastic moves, for when all else has failed.

They will invariably involve losing some data unless your latest Time Machine backup is very recent. Unless you have two Macs, a bootable system on an external drive can really save your bacon.

Sometimes, for example, a bit of software will install a startup item or a library file that doesn't play nicely with your system; or a driver will cause a kernel panic. It's rare but not unheard of. Armed only with a system disc, you couldn't get at the hard drive to view or delete the offending files and would be forced to restore or reinstall.

With a working bootable system, however, you can get the Mac back up and running by holding the Option key during startup with the drive connected over USB2 or FireWire, and then select it as the boot system. Then you can locate and delete the offending items, run an uninstaller or temporarily move or rename folders to see if you can fix the problem.

For environments where backing up is a more commercially sensitive area such as businesses, products like Retrospect 8 might be worth considering. Far more advanced than Time Machine, this is designed to operate in a multi-platform, networked business environment and so while it's more than a home user would need, it could be perfect for a business.

Retrospect 8 for Mac comes in several versions, priced from $85 to $1,250 depending on the number of client licenses included. It has features such as: support for backing up and restoring Windows, Linux and Mac clients; backup to optical disk, tape, NAS and SAN storage devices; support for bootable backups; compression during backup; server admin and AES-256 encryption.

Clearly these are things that a business user would have much more use for than a home user, but they would also need a good technical knowledge. Ideally, a conscientious user should run Time Machine regularly and something like SuperDuper! or Carbon Copy Cloner periodically – and certainly prior to performing major system updates – so that you have both instant access to your backed up files and folders, and a bootable system.

Apple backup

Either a disk image or a full Time Machine backup can be restored to a hard drive in the event of a really serious problem.


First published in MacFormat Issue 218

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