The simplest way to back up your PC

The fastest backup for most people is to plug in an external hard drive and let Windows or macOS handle it automatically. On Windows 10 and 11, you can turn on File History (a built-in tool that saves copies of your files as they change) by going to Settings > System > Storage > Advanced storage options > Backup options, then choosing an external drive. On a Mac, plug in an external drive, open System Settings > General > Time Machine, and click "Use as Backup Disk." Both will run backups in the background without you thinking about it again.

This approach backs up your documents, photos, and settings — the things you actually care about losing. It does not back up Windows or macOS itself, but you can reinstall the operating system from a USB stick if your hard drive fails, then restore your files from the backup. For most people, this is enough.

Key Takeaways

  • External hard drives are the cheapest and most reliable way to back up a PC, and Windows and macOS both have built-in tools to automate the process.
  • File History on Windows and Time Machine on Mac run backups in the background without you having to remember to do anything.
  • A full system image (a complete copy of your entire hard drive) takes longer to create but lets you restore your PC exactly as it was if the drive fails.
  • Keep your backup drive unplugged most of the time so that ransomware or a power surge cannot damage both your PC and your backup at once.
  • Test your backup by actually restoring a file from it before you need it, so you know it works when something goes wrong.

External drives versus cloud storage

An external hard drive (a portable drive you plug into USB) costs $50 to $150 and holds everything you need. It is fast, you own it outright, and it works even if your internet is down. The downside is that if your house floods or burns, the backup burns too. If that risk matters to you, cloud storage (OneDrive, Google Drive, iCloud) backs up your files to a company's servers instead, so a local disaster does not destroy both copies.

Cloud storage is slower to set up initially and costs money if you need more than a few gigabytes — Microsoft OneDrive gives 5 GB free, Google Drive gives 15 GB free, and Apple iCloud gives 5 GB free. Paid plans run $2 to $10 per month for 100 GB to 2 TB. The real advantage is that you can restore a file from anywhere, even if your PC is destroyed. Many people use both: an external drive for speed and a cloud service for protection against total loss.

Full system images versus file backups

A file backup (what File History and Time Machine do) saves only your documents, photos, videos, and settings. If your hard drive fails, you reinstall Windows or macOS from a USB stick, then restore your files. This takes an hour or two but is straightforward.

A system image is a complete copy of your entire hard drive — every program, every setting, every file, exactly as it was. If your drive fails, you restore the image and your PC boots up exactly as it was before, programs and all. The catch is that a system image takes much longer to create (several hours for a full drive), takes up a lot of space on your backup drive, and is harder to restore if something goes wrong. For most people, a file backup is enough. System images are worth doing if you have a lot of programs installed that would be painful to reinstall, or if you cannot afford downtime.

To create a system image on Windows, go to Settings > System > Storage > Advanced storage options > Backup options, scroll down to "Need a backup?", and click "Go to Backup and Restore (Windows 7)." Click "Create a system image" on the left. On a Mac, use a tool like Carbon Copy Cloner or SuperDuper (both paid, around $40) to clone your entire drive to an external disk.

How often to back up and where to store the drive

If you use File History or Time Machine, set it to run daily or weekly depending on how often your files change. If you work with important documents every day, daily is safer. If you mostly browse the web and check email, weekly is fine. Both tools let you choose the schedule when you set them up.

Store your external drive unplugged in a different room from your PC — ideally somewhere cool and dry. Ransomware (malicious software that encrypts your files and demands money) can spread to any drive plugged into your PC, so keeping the backup disconnected means ransomware cannot reach it. A power surge that fries your PC will not fry a drive that is not plugged in. Plug it in once a week or once a month to back up, then unplug it again. If you use cloud storage, it stays backed up automatically, but keep a local external drive too in case your cloud account is hacked.

Testing your backup before you need it

A backup that you have never tested is a backup you cannot trust. Before something breaks, restore a single file from your backup to make sure it actually works. On Windows, right-click a file in File History, choose "Restore personal files," and pick an old version. On a Mac, open Time Machine, navigate to a past date, select a file, and click Restore. If the file comes back, your backup works. If it does not, you have time to fix it.

If you created a system image, test it by booting from the backup drive on another PC (or a borrowed one) to make sure the image is readable. This takes 20 minutes but saves you from discovering during an actual emergency that the image is corrupted.

What to back up and what you can skip

Back up your Documents, Pictures, Videos, Desktop, and Downloads folders — these hold the files you created and care about. Back up your email if you use a desktop client like Outlook or Thunderbird (cloud email like Gmail is already backed up by Google). Back up your browser bookmarks and passwords if you store them locally rather than in a password manager.

You do not need to back up Windows, macOS, or installed programs — you can reinstall them from the original installation media or download them again. You do not need to back up temporary files, cache, or the Recycle Bin. Most backup tools skip these automatically, but if you are creating a system image, you can exclude them to save space.

Backup tools beyond the built-in options

Windows and Mac backups cover most situations, but some people prefer third-party tools. Backblaze is a cloud backup service ($8 per month, unlimited storage) that runs in the background and backs up everything on your PC continuously. Acronis True Image ($50 to $100, one-time or annual) creates system images and file backups with more control over scheduling and what gets backed up. Veeam Backup & Replication is free for personal use and offers detailed control over what, when, and where you back up.

These tools are worth considering if the built-in options feel too limited, but they are not necessary. File History and Time Machine work well for most people and cost nothing.

Frequently Asked Questions

What size external drive do I need?

Get a drive at least as large as your current hard drive, ideally larger. If your PC has a 500 GB drive with 300 GB of files, a 1 TB external drive gives you room to grow and keeps multiple versions of your files. Drives larger than 2 TB are rarely necessary for personal backups.

Can I back up to a USB stick instead of an external hard drive?

USB sticks are too slow and too small for regular backups. They work for backing up a single folder of important documents, but not for continuous backups of your whole PC. External hard drives are faster, cheaper per gigabyte, and designed for this job.

If I back up to the cloud, do I still need an external drive?

Cloud backup alone is risky because if your cloud account is hacked or deleted, your backup is gone too. Keep both: cloud for protection against physical disaster, and an external drive for speed and as a second copy.

How long does a backup take?

The first backup takes the longest — usually 1 to 4 hours depending on how much data you have. After that, File History and Time Machine only back up files that changed since the last backup, so they run in minutes. System images take 2 to 6 hours every time.

What if I accidentally delete a file — can I get it back from my backup?

Yes. File History and Time Machine keep multiple versions of your files going back weeks or months. Right-click the folder where the file was, open the backup tool, navigate to the date before you deleted it, and restore the file. Cloud services like OneDrive and Google Drive also let you recover deleted files for 93 days.