Quick answer
Before reinstalling Windows, save all personal files from the Users folder, browser profiles, email and contacts, license keys and application settings. Be sure to make a copy on an external drive or in the cloud, not just on the partition where Windows is. Check that the copies are readable before you start the installation.
How to recognize the problem
- You are planning to reinstall Windows but do not know what will be lost
- You are not sure where all your files are stored
- You are worried you will lose your Windows or Office license
- You do not know how to save your browser profile and passwords
- You have multiple user accounts on the computer
Most common causes
Reinstallation erases the system partition
When you choose a clean installation, the partition that held the system may be deleted or formatted. Everything on the desktop, in Documents, Downloads and the AppData folder disappears.
Files are scattered across the disk
Many programs by default store data in the user profile or in their own folders, so an important file can easily be missed if you do not check all locations.
Licenses and settings are not tied to an account
Some applications store the license key only locally, not in a cloud account. Without a copy of that data, you will have to buy or request the license again.
Not enough space on another partition
If you copy to another partition on the same disk, you risk that it too will be deleted or run out of space. That is why an external drive or the cloud is a safer solution.
Step-by-step fix
- 1
Make a list of everything you need
Before copying, make a list: documents, photos, video, music, projects, databases, certificates, license keys, program settings. Also write down the names of the applications you use so you can easily restore them later. This list will serve as a checklist later.
- 2
Copy personal folders
Open
C:\Users\[your name](in Explorer on English Windows it appears asUsers) and copy theDesktop,Documents,Downloads,Pictures,VideosandMusicfolders to an external drive; in localized Explorer these folders appear as Desktop, Documents, Downloads, Pictures, Videos and Music. If some of these folders are redirected to OneDrive, also check the contents of the OneDrive folder. If there are multiple user accounts, repeat the procedure for each. Do not forget hidden folders if you use them. - 3
Save the browser profile
In Chrome, go to
chrome://settings/syncSetupand check that sync is turned on. In Edge, it isedge://settings/profiles/sync. If you do not want cloud sync, export passwords and bookmarks to a file via profile settings, but keep that file safe and delete it after restoring. Do the same for Firefox if you use it. - 4
Save email and contacts
If you use Outlook with a POP3 account, export the data to a
.pstfile viaFile > Open & Export > Import/Export. For IMAP accounts, if all messages are on the server, it is enough to know the password. Export contacts and calendar if they are not synced with the cloud. - 5
Review AppData and program folders
In the
C:\Users\[your name]\AppDatafolder (hidden, so turn on showing hidden items) are the settings of many programs (Roaming, Local, LocalLow). Copy only the folders of applications you need, not the entire AppData. Pay special attention to finance, accounting and database programs. - 6
Save license keys and certificates
Find the license key or check the digital license for Windows and Office in emails or on your Microsoft account. If you use digital certificates, export them via
certmgr.mscto a.pfxfile with a password. Keep them separate from other data. - 7
Make a copy on an external drive or in the cloud
Copy everything collected to an external drive that is not connected to the computer during reinstallation. Alternatively, use cloud storage, but check that all files are synced. Never keep the only copy on a partition you will format.
- 8
Check that the copies are valid
Open a few files from the external drive to check that they read. Compare the folder size or number of files with the original. If something is missing, repeat the copy before continuing.
- 9
Write down network and program settings
Note the Wi-Fi network name and password, as well as any static IP addresses. Also write down the program settings you will have to re-enter (e.g. email account, database paths). This will save you time after installation.
If you cannot access the system
If Windows will not boot, you can extract data by connecting the disk to another computer via a SATA or USB adapter. Then copy the user folders and AppData to a safe place. If the disk is encrypted with BitLocker, you will need the recovery key. In that case, do not format the disk until you make a copy. For business computers with multiple users or in a domain, contact the administrator before any reinstallation.
How to prevent it
- Regularly back up according to the 3-2-1 rule, not only before reinstallation
- Keep license keys and certificates in a safe place off the computer
- Use cloud sync for documents and browser profiles
- Before any major change, create a restore point or a full disk copy
When to call a professional
If you have business databases, encrypted disks or multiple users on a network, it is better to leave the reinstallation and backup to an IT professional. They can make a copy of the entire disk and safely restore all data.
IT infrastructure maintenance · Servers, networks, backup, security and helpdeskFAQ
Is it enough to copy only Documents and Pictures?
No, because many programs store data in the AppData folder or in their own folders on the disk. Be sure to check those locations as well, as well as the desktop and Downloads.
How do I save passwords from the browser?
The easiest way is to turn on sync with your account (Google or Microsoft), so the passwords will be restored automatically after reinstallation. If you do not want the cloud, export them to a file via profile settings and keep it safe.
What if I forget to save a file?
After reinstallation, old data may be permanently lost if you did not make a copy. That is why it is mandatory to check all folders and programs before formatting. Always make a copy on an external drive that you will keep separately.