The fastest backup method depends on what you own and how much data you have
A backup is a copy of your files stored somewhere other than your computer — usually an external drive, a cloud service, or both. If your hard drive fails, you get ransomware, or your laptop is stolen, a backup is the only way to recover your work, photos, and settings without paying a technician or losing everything.
Windows and Mac both include free built-in backup tools. Windows has File History and System Image Backup; Mac has Time Machine. These work automatically once you set them up, which means you do not have to remember to back up manually. External hard drives cost between $50 and $150 and hold backups offline, away from internet threats. Cloud services like OneDrive, Google Drive, or Dropbox sync your files to the internet in real time, so you can reach them from any device — but they cost money per month or per year if you need more than a few gigabytes of space.
The best approach is usually a combination: use your operating system's built-in tool to back up your entire computer to an external drive once a week or once a month, and use cloud storage for the files you access most often or need to share.
Key Takeaways
- Windows File History and Mac Time Machine are free and automatic once enabled, and they back up to an external drive you connect to your computer.
- External hard drives cost $50 to $150 and store backups offline, protecting your files from ransomware and internet outages.
- Cloud services like OneDrive, Google Drive, and Dropbox sync files to the internet in real time but charge monthly or yearly fees for storage beyond a few gigabytes.
- The safest setup combines automatic backups to an external drive with cloud storage for files you use daily, so you have both an offline copy and an internet-accessible copy.
How to back up Windows using File History
File History backs up your Documents, Desktop, Downloads, Pictures, Music, and Videos folders automatically. It does not back up your operating system or installed programs — only your personal files. To set it up, plug in an external hard drive, then open Settings by pressing Windows key + I. Go to System, then About, then Advanced system settings. Click System Protection, then Configure, and choose "Restore system settings and previous versions of files." Click OK, then explore.
Next, return to Settings and search for "File History." Click "Back up your files" and select your external drive as the backup location. Windows will then back up your files every hour by default. You can change this interval by searching for "File History" in Settings, clicking Advanced settings, and adjusting the frequency under "Keep my backups." Most people set it to daily or weekly to save drive space.
To restore a file, open File History, click "Restore personal files," navigate to the version you want, and click Restore. If your entire computer fails, you can restore from a system image instead — search for "Create a system image" in Settings, select your external drive, and Windows will create a complete snapshot of your computer that you can restore to a new or repaired drive.
How to back up Mac using Time Machine
Time Machine backs up your entire Mac — files, applications, system settings, and all — to an external drive. Plug in an external hard drive formatted for Mac (most new drives are, but check the manual). Open System Settings, click General, then Time Machine. Click "Add Backup Disk" and select your external drive. Time Machine will then back up automatically every hour while the drive is connected.
The first backup takes several hours because it copies everything on your Mac. After that, Time Machine backs up only the files that changed since the last backup, so subsequent backups are much faster. You can see the backup progress by clicking the Time Machine icon in the menu bar at the top right of your screen.
To restore a file, open Finder, navigate to the folder where the file was, click the Time Machine icon in the menu bar, and use the timeline on the right side to browse previous versions. Select the version you want and click Restore. If your Mac stops working entirely, you can restart it while holding Command + R to enter Recovery Mode, then choose "Restore from Time Machine Backup" to restore your entire system to a previous date.
How to use cloud storage for daily files
Cloud storage services store your files on internet servers instead of your computer. OneDrive (Microsoft), Google Drive (Google), and Dropbox are the most common. Each offers a small amount of free storage — usually 5 to 15 gigabytes — and charges a monthly or yearly fee for more. OneDrive costs $2 per month for 100 gigabytes or $100 per year for 1 terabyte. Google Drive costs $2 per month for 100 gigabytes. Dropbox costs $12 per month for 2 terabytes.
To set up cloud storage, read the app from the service's website, sign in with your account, and choose which folders to sync. Most services let you select specific folders — for example, you might sync your Documents and Photos folders but not your entire hard drive. Files then upload to the cloud automatically whenever you save them. You can reach these files from any device by logging into the service's website or app.
Cloud storage is useful for files you need to access from multiple devices or share with others, but it is not a complete backup because it does not store your operating system, installed programs, or system settings. Use it alongside an external drive backup for full protection.
Choosing between external drives and cloud storage
External hard drives are cheaper upfront and store backups offline, which means ransomware and internet outages cannot touch them. A 2-terabyte external drive costs $60 to $100 and lasts for years. The downside is that you have to physically connect the drive to your computer for backups to happen, and you cannot reach your files from other devices unless you carry the drive with you.
Cloud storage costs money every month or year, but it backs up automatically over the internet and you can reach your files from anywhere. The downside is that your files live on someone else's servers, and if you stop paying, you lose access. Cloud storage is also slower than a local drive for large file transfers.
Most people use both: an external drive for a complete backup of their entire computer, and cloud storage for the files they use most often. This way, if your hard drive fails, you have a full restore point on the external drive. If you lose a single file or need to reach it from your phone, the cloud copy is there.
What to do if your computer fails and you need to restore
If your computer stops working, your first step is to determine whether the hard drive itself is damaged or whether the operating system is corrupted. If the computer turns on but will not start Windows or Mac, restart it in Safe Mode (Windows: restart and press F8 repeatedly; Mac: restart and hold Shift) and try to back up any remaining files to an external drive or cloud storage before attempting a full restore.
If you have a system image backup on an external drive, you can restore your entire computer to the state it was in when the backup was made. On Windows, restart the computer with the external drive connected, press F12 or Delete during startup to enter the boot menu, select the external drive, and choose "Restore from System Image." On Mac, restart while holding Command + R, select "Restore from Time Machine Backup," and follow the prompts.
If the hard drive is physically damaged and will not read, you will need to replace it or take the computer to a technician. A backup on an external drive or cloud storage cannot help you recover data from a failed drive itself, but it means you can restore your files to a new drive without losing anything.
How often you should back up and what to back up
Automatic backups are better than manual ones because they happen without you having to remember. If you use File History or Time Machine, set them to back up daily or weekly depending on how much your files change. If you create or edit files constantly, daily backups make sense. If you mostly browse the internet and check email, weekly is fine.
Back up everything you cannot afford to lose: documents, photos, videos, financial records, and any work files. Do not back up your operating system and installed programs if you are using an external drive with File History, because File History only backs up personal files anyway. If you are using Time Machine on Mac, it backs up everything, which is why the first backup takes so long.
Keep your external drive in a different physical location from your computer if possible — a drawer at work, a friend's house, or a safe deposit box. This protects against theft, fire, or flood. If your external drive is in the same room as your computer and your house burns down, both are gone. Cloud storage automatically solves this problem because the files are stored far away on a company's servers.
Frequently Asked Questions
Can I back up to the same external drive I use for other storage?
Yes, but it is not ideal. If that drive fails, you lose both your backup and your other files. A dedicated external drive for backups only is safer. If you must share a drive, create a separate folder for backups and keep your other files in a different folder, so at least they are organized separately.
What happens if my external drive fails?
You lose that backup, which is why using both an external drive and cloud storage is important. If your external drive fails, your cloud backup is still there. If your computer fails, your external drive backup is still there. If both fail at the same time, you have lost your files — but this is rare.
Do I need to back up if I use cloud storage like OneDrive or Google Drive?
Cloud storage is not a complete backup because it does not store your operating system, installed programs, or system settings. If your hard drive fails, you can restore your personal files from the cloud, but you will have to reinstall Windows or Mac and all your programs. An external drive backup lets you restore everything exactly as it was.
Can I back up to a second computer instead of an external drive?
Yes, but only if the second computer is always on and connected to your network. Most people find an external drive simpler because it does not require another computer to be running. Cloud storage is easier still because it backs up automatically over the internet without any hardware to manage.
How much storage do I need on an external drive?
At least as much as your computer's hard drive. If your computer has a 500-gigabyte drive, get a 1-terabyte external drive so you have room for multiple backup versions. A 2-terabyte drive costs only slightly more and gives you plenty of space for backups over several years.