Time Machine
Back up your files quickly and easily
Time Machine is the built-in backup utility of macOS. When paired with an external drive, it automatically backs up every file on your Mac. Its backups are incremental, meaning that only files changed since Time Machine was last run are saved. This avoids unnecessary duplication of data on the external drive but also means your very first backup may take several hours as every file needs to be copied.
Space permitting, backups are run hourly, and these are then amalgamated into a daily backup which is stored for a month. Daily backups are then collected into weekly backups for the previous month. This is all done automatically for you, and backups are easy to navigate.
To get started, you’ll need to have a dedicated drive to store your backups. The most inexpensive solution is buy an external USB hard drive. Make sure that the capacity of the external drive is at least equal to the Mac’s own hard drive, to be certain there’s enough space. You can check this by clicking on the Apple at the top left of your screen, then About this Mac > Storage.
If you choose to use an external drive, there’s no need to buy one specifically formatted for a Mac. The first time you connect it, macOS will ask if you wish to use it as a backup disk for Time Machine. If you agree to this, it will automatically be formatted. This will mean that any data already on the drive will be lost, which is why it’s best to buy a new one.
Backups can only take place when the drive is physically connected to the Mac. If you are concerned this will be too inconvenient or you won’t remember, you can choose to invest in an Apple Time Capsule, which connects to your router and acts as a Wi-Fi ‘base station’. In other words, it generates its own wireless network, to which your Mac can connect. You can then use AirPort Utility (see below) to set up the Time Capsule.
The device has an internal hard drive (currently either 2TB or 3TB in size) to store your backups. Once this is set up, all backups are performed wirelessly in the background as you use your Mac, meaning you no longer have to worry about connecting cables. This is especially useful if you have more than one Mac, as they can all be backed up to the same Time Capsule. (The latest generation of AirPort Extreme, when you connect a USB drive to it, officially includes this capability as well.)
A question of space
Time Machine is undoubtedly the simplest way to make sure all your Mac files are backed up. Despite storing files incrementally, eventually your backup drive will begin to run out of space.
Time Machine handles this for you by deleting older backups in favour of newer ones, but you may still occasionally see an alert telling you there’s not enough space for new backups. The easiest solution to this is simply to connect a new hard drive and use this as a backup disk instead, preserving your old data. Alternatively, you can choose to exclude specific folders from your backups. Your Downloads folder, for instance, contains files that can often be redownloaded.
Local snapshots
If you own a portable Mac, such as a MacBook Pro, Time Machine will save some backups to your Mac’s own storage if it can’t connect to their usual destination. This feature is enabled automatically when you set up Time Machine, and can only be disabled by switching off Time Machine altogether.
Your Mac deletes local snapshots if your drive has less than 20% free space. Otherwise it keeps one local snapshot every 24 hours and another weekly one, as space allows.
To view local snapshots make sure ‘Show Time Machine in Menu Bar’ is ticked in System Preferences > Time Machine, then click on the small Time Machine icon at the top of your screen, then Enter Time Machine. This allows you to look through your backups. Scroll through the timeline on the right-hand side. Any that are marked in bright red can be restored either from a local snapshot or from the backup drive itself right away, but dimmed red ones require you to connect the drive that contains those backups. Follow the steps at support.apple.com/kb/ PH25540 to restore specific files.
Time travellers
Time Machine supports backing up to multiple disks. Simply go to System Preferences > Time Machine and select a new disk. If you are already using a backup drive, you’ll be given the option to keep using both disks.
This is especially useful if you move your Mac between home and work as you can store disks at different locations. Backups are still incremental in that any changes made since the last backup to a specific disk will be saved to it. If you enter Time Machine, you’ll see the history for all your backup disks.
Time Machine is the simplest way to make sure your files are backed up