A Windows reinstall is easy to start and hard to undo. Before you click Reset or delete a partition, make sure you can rebuild the parts of the PC that Windows will not put back for you.
First, identify which kind of reinstall you are about to run
Windows uses similar language for recovery choices that preserve very different things. Read the confirmation screen for the option on your own PC; do not rely on a tutorial screenshot from another Windows version.
| Recovery choice | What Microsoft says it preserves | What you should assume |
|---|---|---|
| Reinstall through Windows Update | Apps, files, and settings are preserved while the current Windows version is reinstalled. | Back up important data anyway. This option requires a sufficiently updated Windows 11 installation and may be unavailable on work- or school-managed PCs. |
| Reset this PC — Keep my files | Personal files remain, but installed apps are removed and settings return to defaults. | You will need to reinstall programs and may need to rebuild application settings and local data. |
| Reset this PC — Remove everything | Personal files, apps, and settings are removed. | Treat it as destructive. Do not proceed until a separate backup has been opened and checked. |
| Clean install from installation media | A clean reinstall typically removes files, apps, and settings from the Windows installation. | Treat the target Windows partition as disposable. Other partitions survive only if you leave them untouched. |
Make three lists before you copy anything
A quick copy of Documents and Pictures is not enough for many PCs. Write down what belongs in each of these groups so that a familiar folder does not hide a missing category.
- Files you created or collected. Include Desktop, Documents, Downloads, Pictures, Videos, project folders, scanned records, exported photos, and files stored outside your user profile. Check every Windows account that has been used on the PC.
- Data owned by applications. Look for local email archives, accounting or tax files, browser profiles, game saves, virtual machines, Windows Subsystem for Linux distributions, local databases, creative-project libraries, and custom templates. Their storage locations vary by application.
- Things that restore access. Save the BitLocker recovery key, password-manager recovery material, two-factor authentication backup codes, software license information, and the sign-in details for the Microsoft account tied to the PC.
Downloads, a second internal drive, a folder created directly under C:\, another user account, and an application's export folder are common places that sit outside a normal Documents copy.
Confirm what is actually in the cloud
Windows Backup can synchronize selected Desktop, Documents, Pictures, Videos, and Music folders through OneDrive. It can also remember supported Windows settings and an app list. That does not mean every program or every file on the PC has been uploaded.
Open OneDrive on the web from a browser and inspect the folders there. Check the most recent files, not just the green status icons in File Explorer. If OneDrive reports a sync error or insufficient storage, resolve it before reinstalling.
An app list is not the same as an installed application. Microsoft Store apps can be offered again during setup; other apps may only lead you back to the publisher's download page. Keep installers, license details, and application-specific exports when they would be difficult to replace.
Create one copy that is not dependent on sync
Use an external drive with enough free space and copy the important folders to a clearly named directory, such as PRE-REINSTALL-2026-07-30. Copy rather than move, and leave the originals in place until the reinstall begins.
- Open the external drive and confirm it is the intended destination by label and capacity.
- Create separate folders for each Windows user and for application exports.
- Copy irreplaceable files first. Large replaceable downloads can wait.
- Wait for every copy operation to finish, then safely eject and reconnect the drive.
- Open representative documents, photos, videos, archives, and exported application files directly from the backup drive.
For a fuller setup, see how to back up Windows 11 to an external drive. A backup stored on another partition of the same physical disk does not protect you if that disk fails or is erased by mistake during setup.
Save the BitLocker recovery key before changing Windows
Device Encryption or BitLocker may already protect the Windows drive, even if you do not remember turning it on. Confirm the encryption status and make sure the matching 48-digit recovery key is accessible from another device. Do not save the only copy solely on the PC you are about to reset.
Microsoft cannot recreate a missing key. If the PC later requests recovery, the key ID on screen must match the stored key. Our BitLocker recovery-key checklist explains where to look without exposing the secret key.
Record what you will need to reinstall
- Photograph or export the installed-app list, then mark the programs you genuinely need.
- Write down paid software editions, account emails, license types, and any deactivation steps required by the publisher.
- Export bookmarks if browser synchronization is not already verified on another device.
- Download the network and storage drivers recommended by the PC or motherboard manufacturer when the machine depends on unusual hardware.
- Record printer models, VPN settings, mapped network locations, and specialty peripherals that may need separate software.
Do not place passwords or recovery codes in an unencrypted notes file on the backup drive. Store them using the secure method you normally rely on, and make sure you can access that method without this PC.
Decide whether you need a rollback image
A file backup helps you recover documents. A system image serves a different purpose: it can preserve a broader snapshot of Windows, applications, and the captured partitions if you later need to return to the old setup. Creating an image is useful only if you also know which recovery environment can restore it.
If the current Windows installation is unstable, do not make a new image your only backup. Copy irreplaceable files separately first. A corrupted system, failing drive, or incomplete image can reproduce the problem you are trying to escape.
Run this verification before you erase anything
- Can you open the external backup on this PC or another trusted PC?
- Do recent files have the expected dates and sizes?
- Did you check Desktop, Downloads, custom folders, and every user account?
- Can you sign in to the Microsoft account and locate the correct BitLocker key?
- Can you access email, the password manager, and two-factor recovery methods without relying on this Windows installation?
- Do you have installation or recovery media if Windows cannot start afterward?
A folder count or a completed progress bar is not enough. Open several different file types from the destination, including one recent file and one older file that you know well.
If Windows no longer starts
Do not jump straight to Reset this PC. If the drive is still readable and is not showing signs of physical failure, Windows Recovery Environment or another trusted computer may provide a chance to copy files first. An encrypted drive still requires the correct BitLocker key.
If the drive disappears intermittently, makes unusual mechanical noises, or contains irreplaceable data, repeated startup and repair attempts may make the situation worse. Stop and consider professional recovery before writing more data to the drive.
On reinstall day
- Keep the PC connected to reliable power.
- Make sure the recovery key and account details are available on another device.
- Disconnect the verified backup drive before deleting or formatting partitions.
- Leave unrelated internal or external drives disconnected when practical, so the installation target is unambiguous.
- After Windows is running, install updates and essential drivers before reconnecting the backup.
- Restore a small sample first. Do not immediately overwrite newer cloud copies or application data you have not inspected.
Bottom line
The safest pre-reinstall backup is not one enormous copy of C:\. It is a checked set of personal files, application-owned data, recovery credentials, and reinstall information stored somewhere the reset cannot touch. Verify that copy, disconnect it during destructive setup, and keep it unchanged until the rebuilt PC has been used normally for several days.
Official references checked July 30, 2026: Microsoft recovery options in Windows, reinstalling Windows through Windows Update, Windows Backup documentation, and finding a BitLocker recovery key.