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how to decrypt a .text file that i encrypted before formatting

Anonymous
2025-01-03T02:09:06+00:00

am asking for yur help please, i had some important .text files i encrypt it with windows option and kept opening and using it normally, but when i format the pc, i moved my files into D disk (second partition on the same laptop) i thought am fine and i saved my files safely and it was right, but then after i formatted partition C with a new windows and starting to mugrate back my files i found that the .text files are not opening and refusing to be decrypted.. i tried all the found tutorials or methods from old threads or forums but it did not work (trying to decrypt by windows/ going to property--Security--change ownership/ take ownership/ with CMD/ etc... not working, so tell me pls if i have just to give up or you may have a solution that may help and thats will be great. thanks in advance in all cases.

Windows for home | Windows 11 | Security and privacy

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  1. Anonymous
    2025-01-10T12:39:45+00:00

    Dear Rez9 Rez9

    Thank you for posting in the Microsoft community.

    I'm sorry to hear you're experiencing this issue.

    This is a common scenario around Windows file encryption (EFS, Encrypting File System): i.e., after files have been encrypted, if user accounts and certificates on the system are removed (e.g., by formatting or reinstalling the system), these encrypted files cannot be accessed or decrypted unless you have backed up the necessary keys and certificates beforehand.

    Why does decryption fail

    1. Windows uses EFS technology to encrypt files. By default, EFS generates encryption keys (also known as “certificates”) to encrypt files based on your user account.
    2. These keys are stored on the local system. If you format the C drive, overwrite/delete your user account or Windows installation, the private key required for decryption will be lost.
    3. Even if you save the file, missing the certificate and key, Windows can no longer access the encrypted data of the file.

    Situation analysis: Is it possible to recover the files

    Whether you can recover the file or not depends entirely on the following points:

    1. Have you backed up the certificate and key

    If you exported the EFS key or certificate before formatting, you can re-import and decrypt the file.

    1. Is there an old system image or undeleted Windows backup?

    Check to see if there are any system backups, restore points, or content transferred to an external device.

    1. Have old accounts and passwords been reset

    An exact match user account was created (including the same username and password), which may be useful in some cases (not common).

    1. Was a third-party tool used to decrypt?

    Without keys and certificates, it is very difficult to decrypt the files, as they are protected by strong encryption (and very long time to break them by force). However, tools are still available to try to recover the data.

    Check if the encryption key (certificate) is backed up

    -If, when encrypting a file, Windows prompts you to back up the file's encryption certificate and export it (usually generating a .pfx file), this will be the most effective decryption solution.

    -Check to see if the certificate was ever saved, possible locations include:

    USB flash drive or external hard disk.

    Local file: file name similar to *.pfx.

    Backup via email or cloud.

    Steps: Restore the encryption certificate to the system

    1. Import the certificate:

    Copy the .pfx file to the current system.

    Press Win + R, type mmc, and press Enter.

    In the console window, go to File -> Add/Remove Management Units -> Certificates -> My User Accounts. o On the left side, navigate to Certificates.

    Navigate to Certificates -> Personal on the left hand side and right click Import.

    Browse and select the .pfx file and complete the import.

    2. Decrypt the file:

    Locate the encrypted file, right click and select Properties -> Advanced. o Uncheck the “Encrypted File” box.

    Uncheck “Encrypt content to protect data”.

    If the certificate matches, the file should be decrypted successfully.

    Trying to recover the private key file using an old system or backup

    If the .pfx file cannot be found, check for an old backup file or system image, which may still contain the encryption key.

    Check the system backup/image:

    1. If you have created a system interface using the backup that came with Windows or another tool such as Acronis True Image, try restoring the old system before formatting the C: drive.
    2. After entering the old system, export the certificate:

    Press win+s to search for Powershell>Run as administrator and enter

    cipher /x backup_e

    (After exporting, it will prompt to save the created file and also generate an encrypted certificate file.)

    Check the restore point:

    1. If your system has used Windows System Restore Points, these points may also contain certificate and key data.
    2. Restore method:

    Open Startup Menu -> Recovery -> Open System Restore on an existing system.

    Find an older restore point and export the data.

    Letting go of encrypted files

    If the key or any backup cannot be found, the file may be lost forever.Windows EFS uses a strong encryption design that makes decryption next to impossible without the key.

    Tips for the next time encryption is enabled:

    1. Always back up your certificate and key:

    Each time you use EFS to encrypt a new file, new keys are generated, so you need to back up these keys.

    1. Use EFS encryption with caution:

    If you are not familiar with EFS or use it for personal use, consider using other backup and encryption tools (e.g. WinRAR, 7-Zip's encryption, BitLocker, VeraCrypt).

    1. Store important data and system partitions separately:

    Avoid storing system files and important data in the same partition to reduce formatting risk

    Best Wish

    Shawn.Z-MSFT | Microsoft Community Support Specialist

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