There are two types of computer users in the world: those who have lost all of their data to a crashed hard drive, and those who eventually will. Relying solely on the internal storage of your laptop to safeguard years of family photos and critical work documents is incredibly dangerous.
To protect your data, Apple built an automated, seamless backup utility directly into macOS called “Time Machine.” It takes a snapshot of your entire computer every single hour. If you accidentally delete a file, or if your Mac’s internal logic board completely fails, you can use Time Machine to restore everything exactly as it was. All you need is an external hard drive.
This guide explains how to set up and use Time Machine on your Mac.
Step 1: Prepare the External Drive
First, you must purchase an external USB hard drive or solid-state drive (SSD). Ideally, the capacity of the external drive should be at least twice the size of your Mac’s internal storage (e.g., if you have a 512GB Mac, buy a 1TB external drive). This extra space allows Time Machine to keep months of historical data.
- Plug the external hard drive into your Mac using a USB cable.
- Often, simply plugging in a blank drive will prompt macOS to display a pop-up window asking: “Do you want to use this drive to back up with Time Machine?” If you see this, click Use as Backup Disk and skip to Step 3.
- If you do not see a pop-up, click the Apple menu () in the top-left corner of your screen and select System Settings.
- In the left-hand sidebar, click on General, and then click on Time Machine on the right.
Step 2: Select Your Backup Destination
If you had to manually navigate to the System Settings menu, you now need to point Time Machine at the drive you just plugged in.
- Click the button labeled Add Backup Disk.
- A list of available drives will appear. Select your new external hard drive from the list.
- Click Set Up Disk.
- macOS will warn you that the drive must be erased and reformatted to work with Time Machine. Warning: This will delete everything currently on that external drive. Assuming the drive is brand new or contains no important data, click Erase.
Step 3: Let Time Machine Run
Once configured, Time Machine requires absolutely no further interaction from you.
It will immediately begin its first backup, copying every single file, application, and setting from your Mac to the external drive. Depending on how much data you have, this initial backup could take several hours. Do not unplug the drive or turn off your Mac during this time.
After the first backup is complete, Time Machine operates invisibly in the background. As long as the external drive is plugged in, macOS will quietly save hourly backups of the past 24 hours, daily backups for the past month, and weekly backups for all previous months. When the external drive eventually fills up completely, Time Machine automatically deletes the oldest backups to make room for new ones, ensuring you are always protected.