Backing up your Mac is a perennially important topic that has grown in importance in the past 10 years. The files we store relate to many aspects of our lives. Purchases can be recovered at expense, but hardware failure and physical trauma could lead to your personal mementos being lost forever, or incur costly delays to your business.

Rather than seeing backing up as a chore, consider it part of the convenience of using computers, and with the advent of Time Machine, Apple’s own backup software built into Mac OS X, it couldn’t be simpler. However, employing a single backup solution remains risky. The smartest option is to invest for your future by adopting a combination of the following strategies.

Read more: Best Mac backup software | How to back up a Mac

Bootable duplicate of your startup disk

A clone of your Mac’s startup disk gives you a complete working system to fall back on if the startup disk becomes damaged. Your Mac can be up and running again in minutes, with continued access to your mission-critical apps. Clones can be made with Apple’s Disk Utility, but Carbon Copy Cloner and SuperDuper are better (and free) options as they are able to update a duplicated system without starting from scratch each time. Alternatively, ChronoSync ($40 [£25], addresses this scenario and versioned backups in one app.

Carbon Copy Cloner

The clone shouldn’t be updated frequently. It should only reflect big changes to important apps and their configuration, and only after verifying that software updates do not introduce any show-stopping issues to your workflow. The clone needs to be a snapshot of your system in tip-top working order.

To start your Mac from a cloned system, hold down the Option key when you hear the startup chime until a list of attached bootable volumes appears. Once you’re at the desktop, the choice can be made to persist between restarts, until you have time to repair the internal disk, by choosing the clone in System Preferences’ Startup Disk pane.

By cloning your disk you minimise the inconvenience of downtime caused by sudden hard drive corruption or hardware failure. It eases the pressure to fix the problem immediately, so you can still hit your deadlines. Once the internal disk has been replaced, the bootable duplicate can be cloned back to the new disk after you’ve formatted it with a Mac OS Extended (Journaled) file system using Disk Utility.

We mentioned that the clone should represent a clean working state. That’s to prevent damage to files on your regular startup disk being replicated on the clone, rendering it unusable. With your operating system and apps covered, this type of backup needs to be complemented with another to cover your day-to-day work.

Versioned backup

Macs running Leopard or later can use the built-in Time Machine feature for versioned backups. It requires an external hard drive. Consider Apple’s networked Time Capsule with a MacBook if you might forget to connect an external drive, and to back up multiple Macs without purchasing drives for each one.


Time Machine backs up changed files on an hourly schedule. It retains older versions and trims their number as available disk space becomes depleted. You should lose no more than an hour’s work if a file becomes damaged or gets accidentally thrown out with the trash. However, save frequently in apps that don’t do so automatically, so that changes are picked up.

Individual files can be recovered by clicking the Time Machine’s menu bar icon and choosing Enter Time Machine. In the event of total system failure, they can be restored to another Mac by connecting the drive, holding down the Option key when clicking the menu bar icon and choosing Browse Other Time Machine Disks.

Unlike a cloned copy of your system, the way files are stored prevents you booting your Mac from a Time Machine backup, even though it preserves your whole operating system as well as documents. However, it can be restored by starting from your latest install DVD and choosing Utilities > Restore System from Backup. This lets you roll back to a previous state if a software update introduces a problem. Before installing new software, force a backup outside of the hourly schedule by clicking the menu bar icon and choosing Back Up Now.

Time Machine doesn’t encrypt backups, which is an issue for business data that’s covered by the Data Protection Act. Since the backup is stored close to the original, it’s just as susceptible to theft and physical damage from fire and flooding. Time Machine doesn’t let you back up to other types of media.

Alternative backup apps such as ChronoSync are more flexible. It can back up multiple versions of files and to multiple destinations: an external hard drive or an iPod with disk mode, a set of optical discs and a NAS drive. With the optional ChronoAgent add-on ($10, [£6.13]), one Mac can act as a backup server for others.

Online backup

An online backup is vital in case the originals and backups stored at the same location are destroyed. The initial backup time is dictated by the upload speed of your internet connection, which is often much slower than your download speed. With a hard drive that’s well organised, identify folders that contain your most critical files and add them to the schedule first. Once complete, add other files in batches and in order of importance.

MobileMe Backup

High capacity online storage is affordable for home and business use alike, but pricing structures are varied. You may only need the amount that’s provided for free. Apple’s MobileMe service gives you 20GB of storage, which can be used to transfer files between Macs using the Finder’s Go > iDisk menu, and using MobileMe Backup (see However, you’re paying for many surplus features if backup is all you need, so look at dedicated providers.

Dropbox ( starts at $9.99 (£6.11) for 50GB of space, and SugarSync ( begins at 30GB, with monthly and annual plans starting at $4.99 (£3.05) per month or $49.99 (£30.60) per year.

If widely spaced capped capacities don’t work for you, Jungle Disk ( provides Amazon S3 and Rackspace storage options that charge for what you use. Past 5GB, they cost 14 cents (8p) and 15 cents (9p) per gigabyte, respectively. However, the Amazon S3 option incurs charges of 10 cents (6p) and 15 cents (9p) for each gigabyte uploaded and downloaded, respectively. SpiderOak ( charges in $10 (£6.13) increments for every 100GB that you store.

Mozy ( charges £4.99 a month per computer for as much space as you need. It only stores versions of files dating back 30 days, which might matter for long projects. Likewise, Backblaze ( costs $5 (£3.07) a month per computer for unlimited storage.

CrashPlan ( offers 10GB and unlimited tiers, starting at $2.50 (£1.54) and $5 (£3.07) per month for one computer, respectively. Unlimited backups from multiple computers start at $12 (£7.38) per month, and long-term subscriptions reduce these prices. Its free software offers the option of backing up to storage attached to a friend’s computer, from which you can quickly recover by borrowing the drive. Some services, including CrashPlan, will return data on DVDs or a hard drive for a fee, which is useful if download speed will exceed the estimated delivery time.

When choosing a provider, check that the connection to its server is encrypted – typically that’s done using SSL – and that files are stored in an encrypted form, using a secure password that you get to choose. Protecting information against interception and determined hackers is especially important if you deal with information that falls within the remit of the Data Protection Act; the Information Commissioner’s Office provides advice at

Even with a paid service, plan for the worst:  your provider going out of business. Check the terms and conditions of service. They may contain a clause that says the company will attempt to keep its service running for a few days. If catastrophe coincidentally strikes at the same time, the duration could be insufficient to recover everything, especially if the service is subjected to heavy demand from less clued-up people who are exclusively using online backup. A robust backup plan uses a combination of the various methods. A local backup offers speed in non-catastrophic scenarios that online recovery can’t compete with. If disaster strikes, you’ll be glad you covered all the options.

What kind of storage and how much?

Capacity is the critical issue when choosing storage for backups, and how much you buy depends on the level of protection you need and the type of drive that provides it. Drives that contain a single disk offer no fallback if they fail at the same time as your startup disk. The distinction between USB 2.0 and FireWire 800 ports might seem to matter less once you’ve made your initial full backup. Incremental runs that follow are less time-consuming. However, FireWire 800 could be worthwhile if you need to restore a system that’s hundreds of gigabytes in size.

Some drives contain multiple disks and support various RAID levels, whereby the disks operate in concert for speed or redundancy. Depending on the mode you choose, the disk capacity can be anywhere between 100 per cent and 50 per cent of the advertised capacity, depending on how much protection you want against one or more of the disks failing.

There’s also the issue of whether you’re backing up a single Mac or several. Apple’s Time Capsule is a straightforward way to back up several Macs using Time Machine, although available capacities are limited to 1TB and 2TB. Files can also be stored on it in user folders.

NAS drives offer features, including media and print servers, user groups, disk quotas, and ports to connect cameras and copy straight to the drive.

Pick a drive that’s too small and Time Machine will quickly run out of space, forcing the number of old versions to be trimmed. Begin to calculate the space you’ll need by checking the total amount of space used on your Mac’s startup disk, open a Finder window, select Macintosh HD (or whatever you’ve renamed the volume) then choose File > Get Info. Under the General heading you’ll see the total capacity, and how much of it is used.

If you have moved iTunes or your iPhoto library to an external drive, use the same technique to find out how much is used on those drives. Time Machine and other apps can back them up too.

Once you have tallied up the total used space across all hard drives that need backing up, remember that Time Machine uses slightly more than this amount to store the current version of each file, and to keep track of everything it stores.

Look for a drive that is 1.5 times as big as the space used across all your drives. If that’s impossible (single-disk drives currently top out at 3TB), consider purchasing another drive to hold a backup of any media libraries stored on external drives. Carbon Copy Cloner can be scheduled to clone one drive to another.

A larger drive might seem excessive, but there’s not much difference in price between single-disk 1TB and 2TB drives and you are sure to fill it if you take lots of photos and video.

If budget permits, get a second external drive for a bootable duplicate. It needn’t be attached to run Time Machine, and so can be stored more safely away from your Mac.

When creating a bootable duplicate in Carbon Copy Cloner, choose to make an incremental backup that excludes the contents of folders such as Documents and Movies, which don’t need to be stored on the bootable clone; anything you need from them can be recovered from your Time Machine backup.