What to back up before a fresh Windows install

Before you reinstall Windows, you need to save three categories of things: your personal files (documents, photos, videos, downloads), your program settings and data (browser bookmarks, email accounts, game saves), and a list of which programs you have installed. Windows reinstallation wipes your entire drive, so anything not backed up will be gone. Most people focus only on files and forget settings, then spend weeks reconfiguring everything afterward.

A fresh Windows install takes 30 minutes to 2 hours depending on your internet speed and drive size. The actual backup takes longer — usually 1 to 4 hours for a typical personal computer, depending on how much data you have. Plan for a full day if you want to do this carefully.

Key Takeaways

  • Back up your Documents, Pictures, Downloads, Desktop, and Videos folders to an external drive or cloud storage before you start.
  • Export your browser bookmarks, email accounts, and any program settings you want to keep — these do not transfer automatically during a fresh install.
  • Make a list of the programs you have installed now so you know what to reinstall afterward; use a free tool like Ninite to download them all at once.
  • Use an external hard drive or USB drive with at least as much free space as your total backup size, or use cloud storage like OneDrive or Google Drive.
  • Test that your backup actually works by opening a few files from it before you wipe your PC.

Back up your personal files to an external drive

The fastest way to back up files is to plug in an external hard drive and copy your main folders to it. You need a drive with enough free space — if your Documents, Pictures, Downloads, and Desktop folders total 200 GB, you need a drive with at least 250 GB free. External drives cost $50 to $150 depending on size and are reusable for future backups.

Open File Explorer and navigate to C:\Users\[YourUsername]. You will see folders named Documents, Pictures, Downloads, Desktop, Videos, and Music. Right-click each one, select Copy, then navigate to your external drive and select Paste. This takes time if you have a lot of files — a 500 GB backup over USB 3.0 takes roughly 1 to 2 hours. Leave your computer plugged in and do not unplug the drive until the copy finishes.

If you have files scattered in other locations — a folder on your Desktop called "Projects" or files in a work folder — copy those too. Check your Downloads folder especially; many people accumulate gigabytes of installers and old files there that they do not realize they have.

Use cloud storage for files you access from multiple devices

If you use OneDrive, Google Drive, Dropbox, or another cloud service, files stored there are already backed up and will sync to your new Windows install automatically once you sign in. You do not need to do anything extra for those files. However, if you have files in your Documents or Downloads folders that are not in a cloud folder, they will not sync and you must back them up manually.

If you do not currently use cloud storage but have important files, you can upload them now before the reinstall. Google Drive and OneDrive both offer free accounts with 15 GB and 5 GB of storage respectively. Upload your most important documents and photos there, then after your fresh install, sign in and download them back. This is slower than an external drive but works if you do not have one available.

Export your browser bookmarks and email accounts

Your browser bookmarks, saved passwords, and email accounts do not transfer during a Windows reinstall. You must export them manually. Open your browser — whether it is Chrome, Firefox, Edge, or Safari — and look for a menu option called Bookmarks or Settings. In Chrome, go to Settings > Bookmarks > Bookmark Manager, then click the three dots and select Export Bookmarks. Save the file to your external drive or email it to yourself.

For Firefox, go to Bookmarks > Manage Bookmarks > Import and Backup > Backup. For Edge, go to Settings > Profiles > Favorites and look for an export option. Each browser stores this differently, so search "[Your Browser Name] export bookmarks" if you cannot find it.

For email, if you use Gmail, Outlook, or Yahoo through a web browser, your emails stay on their servers and will appear again once you sign in after the reinstall. If you use a desktop email program like Outlook or Thunderbird, export your email folders before you reinstall. In Outlook, go to File > Open & Export > Import/Export and choose to export to a file. Save it to your external drive.

Make a list of your installed programs

After a fresh Windows install, you will need to reinstall all your programs. The easiest way to remember which ones you have is to make a list now. Open the Windows Start menu and scroll through your installed programs, or go to Settings > Apps > Apps & Features to see a complete list. Write down or screenshot the names of programs you actually use — do not include Windows built-in programs like Notepad or Calculator.

A faster method is to use a free tool called Ninite. Go to ninite.com, check the boxes next to the programs you have installed (it lists common ones like Chrome, Firefox, VLC, 7-Zip, and dozens more), and download the installer. After your fresh Windows install, run that same Ninite installer and it will download and install all of them at once, saving you hours of clicking through individual installers.

For programs that are not on Ninite's list, write down their names and where you got them. If you bought software like Microsoft Office or Adobe Creative Suite, make sure you know your login credentials before you reinstall Windows — you will need them to reactivate the software afterward.

Back up your Windows license key and system information

If you are running Windows 10 or Windows 11, your license is usually tied to your Microsoft account, so you do not need to do anything. Once you reinstall Windows and sign in with the same Microsoft account, it will activate automatically. However, if you have an older Windows version or a standalone license key, write it down or take a photo of it now.

You can also find your current Windows product key using a free tool. Search for "Belarc Advisor" or "Speccy" — both are free programs that show your Windows key and other system information. Run one of them, find your product key in the results, and save it somewhere safe like a note in your email or a document on your external drive.

Test your backup before you reinstall

Before you wipe your PC and reinstall Windows, verify that your backup actually works. Unplug your external drive, then plug it back in and try to open a few files from it. Open a document, play a photo, or run a program from the backup drive. If the files are corrupted or missing, you will find out now instead of after your reinstall.

Also test that you can sign into your cloud storage accounts and see your files there. If you exported bookmarks or email, open those files and make sure they are readable. This takes 15 minutes and can save you from losing important data.

Frequently Asked Questions

Do I need to back up Windows itself, or just my files?

You only need to back up your personal files and settings. Windows itself will be freshly installed from Microsoft's installation media, so there is no reason to back it up. Backing up Windows would actually defeat the purpose of a fresh install, which is to remove old files and corrupted system data.

What if my external drive is not big enough for everything?

Back up in stages. Copy your most important files first — Documents, Pictures, and Desktop. Then unplug the drive, copy those files to cloud storage or email them to yourself, and use the same external drive to back up your remaining files. You can also delete old files you no longer need before backing up, which frees up space.

Will my programs work after I reinstall Windows?

Most programs will work fine after a fresh install, but you must reinstall them. Simply copying a program folder from your backup and pasting it into your new Windows will not work — programs need to register themselves with Windows during installation. Use Ninite or download installers from each program's official website.

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

Yes, if your files are small enough. A typical USB flash drive holds 32 GB to 256 GB. If your backup is larger than your drive's capacity, you will need an external hard drive or cloud storage. USB drives are also slower than external hard drives, so a large backup will take longer.

What happens to my programs if I do not back them up?

They will be completely removed during the fresh install. You will need to reinstall them from scratch using their original installers or download links. This is why making a list of your programs now is important — you will know what to reinstall and where to find them.