Published 2021-11-15 by TechNet New England
Backing up your computer to an external drive is one of the simplest and most effective ways to protect your data. If your hard drive fails, your laptop is stolen, or ransomware encrypts your files, an external backup lets you recover. ## Windows: File History and Backup ### Using File History (Recommended for Ongoing Backup) 1. Connect an external USB drive to your computer. 2. Go to **Settings > System > Storage > Advanced storage settings > Backup options**. 3. Click **Add a drive** and select your external drive. 4. Toggle **Automatically back up my files** to On. 5. Click **More options** to configure what gets backed up and how often. File History continuously backs up files from your Desktop, Documents, Pictures, Videos, and other folders. You can restore individual files or folders from previous versions. ### Using Windows Backup (System Image) For a full system backup that includes Windows, applications, and all files: 1. Search for **Control Panel** and open it. 2. Go to **System and Security > Backup and Restore (Windows 7)**. 3. Click **Create a system image**. 4. Select your external drive as the destination. 5. Click **Start backup**. This creates a full image you can restore from if Windows becomes unbootable. ## Mac: Time Machine Time Machine is the built-in backup solution for macOS. It creates incremental backups of your entire Mac. ### Set Up Time Machine 1. Connect an external USB drive to your Mac. 2. macOS will usually ask if you want to use the drive for Time Machine. Click **Use as Backup Disk**. 3. If it does not ask automatically, go to **System Settings > General > Time Machine**. 4. Click **Add Backup Disk** and select your external drive. 5. Time Machine will format the drive (if needed) and start the first backup. ### How It Works Time Machine backs up your entire Mac: system files, applications, accounts, settings, and all user files. It runs automatically every hour when the drive is connected. The first backup takes the longest (it copies everything). After that, only changes are backed up, so subsequent backups are faster. ### Restore Files 1. Open **Time Machine** from the menu bar icon or Applications. 2. Navigate through the timeline on the right side of the screen. 3. Find the file or folder you want to restore. 4. Click **Restore**. ### Restore Entire Mac If you need to restore your entire Mac (after a drive replacement or clean install): 1. Boot into Recovery Mode (hold Command + R on Intel Macs, or hold power button on Apple Silicon). 2. Select **Restore from Time Machine Backup**. 3. Choose your backup drive and the backup date. 4. Follow the prompts. ## Best Practices **Keep the external drive disconnected when not backing up** (if you are concerned about ransomware encrypting the backup). **Use a drive at least twice the size of your internal storage.** Time Machine and File History keep multiple versions of files, which requires extra space. **Test your backup periodically.** Try restoring a file to make sure the backup is actually working. **Do not rely on just one backup.** Consider a second backup to a different drive or a cloud backup service for additional protection. **Label your backup drive** and keep it in a safe location.