How To Backup Your Computer

Backing up your computer protects your photos, documents, and settings from hard drive failure, accidental deletion, or malware. This guide shows you the safest way to create a full backup using built-in tools and an external drive. The most important thing to understand is that a backup only protects you if it is stored separately from your computer.

Fast Answer

Best method: Use File History (Windows) or Time Machine (Mac) with an external hard drive
Rule to follow: Keep at least two copies of your files, with one stored off-site

30-60 minutes Time needed

Beginner Difficulty

External drive size Watch out for

Before You Start

An external hard drive or large USB flash drive with at least twice the space of the files you want to back up.
Your computer plugged into a power source to prevent it from sleeping or shutting down during the backup.
Your user account password and administrator access on the computer.
A stable internet connection if you also plan to use a cloud backup service.

Check first: Verify your external drive has enough free space before you start. A backup that stops halfway because the drive is full is not a backup at all, and it will not protect your files.

Step-by-Step Instructions

Connect Your External Drive and Check Its Space

Plug your external hard drive or USB flash drive into a USB port on your computer. Wait for the operating system to recognise the drive. Open File Explorer on Windows or Finder on Mac, then right-click the drive and select Properties or Get Info.

Look at the capacity and the available free space. You need enough room to hold everything you want to protect. If you are backing up an entire computer with lots of photos or video, a drive that is at least the same size as your computer's internal storage is a safe starting point. For most users, a 1TB external drive provides plenty of room.

Tip: Use a drive that is new or recently formatted. Old drives can fail without warning, so do not rely on a drive that has been sitting in a drawer for years.

Open the Built-In Backup Tool

On Windows, open the Start menu and type "File History" or "Backup settings," then press Enter. On a Mac, click the Apple menu in the top-left corner, select System Settings, then click General, and finally Time Machine.

These built-in tools are free and designed specifically for backing up your personal files. They work in the background after the first backup, so you do not need to remember to run them manually. Do not download third-party backup software unless you specifically need a feature these tools do not offer.

Tip: Windows also offers a second tool called Backup and Restore. It has been available since older versions of Windows and still works well, but File History is easier to set up and better suited for personal files.

Select Your External Drive as the Backup Destination

In File History, click "Add a drive" and choose your external drive from the list. In Time Machine, click "Add Backup Disk" and select your drive. The system may ask if you want to erase the drive or use it for backups only. Follow the on-screen prompts to complete the setup.

If you do not see your drive listed, unplug it and plug it back in. Sometimes the computer needs a moment to recognise the drive. Make sure the drive is formatted correctly. Windows uses NTFS by default, and Macs use APFS or HFS+. A drive formatted for one system may not appear on the other without reformatting.

Important: If the system asks whether to erase the drive, be certain there are no files on it you need. Formatting erases everything on the drive permanently.

Choose What to Back Up

File History backs up your Libraries, Desktop, Contacts, and Favourites by default. To add more folders, click "More options" and then "Add a folder." On a Mac, Time Machine automatically backs up everything on your internal drive except system files that change constantly.

Think about where you store your important files. Photos, videos, documents, spreadsheets, and saved game files are all worth protecting. Consider whether you have files in unusual locations, such as a separate hard drive partition or a downloads folder that you rarely clean out.

Tip: Do not back up temporary files, browser caches, or large program installations. These can be recreated or reinstalled, and they take up valuable backup space.

Start the First Backup

In Windows File History, click "Back up now." In Time Machine, click the Time Machine menu icon in the menu bar and select "Back Up Now." The first backup will take a while, anywhere from 20 minutes to several hours depending on how much data you have and how fast your drive is.

Leave your computer plugged in and awake while the backup runs. If your laptop goes to sleep, the backup will pause. You can keep using your computer normally while the backup runs in the background, but heavy tasks like video editing may slow down the process.

Tip: Start your first backup overnight or while you are at work. A large backup does not need your attention, but it does need the computer to stay on.

Verify the Backup Completed Successfully

After the backup finishes, check that it actually saved your files. In Windows, open File History and click "Restore personal files" to browse the backed-up versions. In Time Machine, open the Time Machine window and scroll through the timeline to see your files.

Open a few files from the backup to confirm they open correctly. This step is often skipped, but it is the only way to be sure your backup will work when you need it. A backup with corrupted files gives you a false sense of security.

Check first: If the backup reports an error, read the error message carefully. It often points to a specific file or folder that caused the problem. Fix that issue before running the backup again.

Set Automatic Backups

Windows File History runs automatically every hour by default. To change this, go to "More options" and adjust the "Back up my files" dropdown. Time Machine backs up every hour as well. You can change the frequency from the Time Machine settings.

Automatic backups are the key to permanent protection. If you only back up manually once a month, you will lose anything created in the weeks since your last backup. Let the system handle this in the background so you can focus on your work.

Tip: Keep a note on your calendar to check that the external drive is still connected and the backup is running properly at least once a month.

Store a Copy Away from Your Computer

Once your external drive backup is running smoothly, create a second copy. This can be a cloud backup service or a second external drive you keep at work, at a friend's house, or in a fireproof safe. The point is to protect against theft, fire, flood, or any disaster that could destroy your computer and the backup drive sitting next to it.

Cloud services run automatically once installed and require no effort after setup. If you prefer a second physical drive, plug it in once a week or once a month and run a manual backup. Many people use both: automatic cloud backup plus a weekly external drive copy.

Tip: The 3-2-1 rule is simple to remember: keep 3 copies of your data, on 2 different types of storage, with 1 copy stored off-site.

Test Restoring a File

Find a small file you know exists in the backup, then restore it to your desktop. In Windows, open File History, click "Restore personal files," find the file, and click the green restore button. In Time Machine, navigate to the file in the timeline and click "Restore."

Testing a restore confirms that your backup format is readable and that the process works. It also gives you confidence for the moment when you have to restore everything after a crash. If you have never restored a file, the first time you need to do it should not be in an emergency.

Tip: Practice restoring a folder full of files, not just one document. This checks that larger restores work correctly as well.

Quick Reference

Situation	Use this	Why
Windows computer	File History	Built-in, free, and runs automatically every hour
Mac computer	Time Machine	Backs up your entire system and makes restoring simple
Protection against theft or fire	Cloud backup or second drive stored off-site	A single drive next to your computer will not survive a disaster
Monthly manual check	Quick restore test of one file	Confirms your backup is still working and readable
Recovering an old version of a document	File History or Time Machine version history	Both tools save multiple versions of your files over time

FAQ

Common Issues

If the result is not working as expected, return to the previous step, check the material or setting involved, and make one adjustment at a time for how to backup your computer.

Advanced Tips

Once the basics are consistent, change only one variable at a time and keep notes on what improves the result for how to backup your computer.

Final Checklist

Confirm the key measurement or setting.
Check the result in normal daily use.
Store the care notes for the next time.

What should I check before using this advice?

Check the current details that apply to how to backup your computer, including availability, local rules, timing, compatibility, and any personal constraints.

Who is this guidance best for?

It is written for readers who want a practical starting point and are prepared to compare the advice with their own situation before acting.

What is the simplest next step?

Start with the first low-risk action, check the result, and make one adjustment at a time rather than changing several things at once.