How to Use EFS to Encrypt Files in Windows

If you want to protect sensitive files on your Windows PC from unauthorized access, the Encrypting File System (EFS) is a built-in tool designed just for that. EFS lets you encrypt individual files or folders so only your user account can open them. In this article, we’ll walk you through how to use EFS to encrypt your files and highlight important things to keep in mind.

What is EFS?

EFS, or Encrypting File System, is a Windows feature that provides file-level encryption. Unlike full disk encryption tools like BitLocker, EFS protects specific files and folders by encrypting them on NTFS drives. This means even if someone has physical access to your computer or hard drive, they can’t read your encrypted files without your Windows login credentials.

Steps to Encrypt Files Using EFS

1. Open Properties

Right-click the file or folder you want to encrypt, and select Properties.

2. Go to Advanced Attributes

In the General tab, click the Advanced… button.

3. Enable Encryption

Check the box next to Encrypt contents to secure data.

4. Apply Changes

Click OK, then Apply. If you selected a folder, you’ll be asked if you want to encrypt just the folder or the folder, subfolders, and files. Choose according to your needs.

If you are encrypting a file that is in an unencrypted folder, you will be asked whether you want to encrypt the file and its parent folder, or just the file. Make your selection based on your needs.

5. Backup Your Encryption Key

The first time you encrypt a file, Windows will prompt you to back up your encryption certificate and key. This is very important. If you lose this key, you won’t be able to access your encrypted files on a new computer or after reinstalling the OS.

Finally, you'll see a yellow lock in the upper right corner of the file thumbnail, and the file name's color will change to green. This indicates the file is encrypted.

Important Things to Know When Using EFS

1. Only Works on NTFS Drives

EFS encryption requires the drive to be formatted with NTFS. It won’t work on FAT32 or exFAT drives.

2. Tied to Your User Account

Only the Windows user account that encrypted the file can decrypt it. Other accounts, even administrators, cannot access the encrypted files unless they have the encryption key.

3. Backup Your Encryption Key

Losing your encryption certificate or key means losing access to your encrypted files forever. Always export and save your key in a safe place.

4. Not a Substitute for Full Disk Encryption

EFS protects individual files, but it doesn’t secure the entire disk. For full disk protection, consider using BitLocker alongside EFS.

5. Sharing Encrypted Files

Encrypted files cannot be opened by other users or computers unless the encryption key is shared, which is generally not recommended for security reasons.

6. Performance Impact

EFS has minimal impact on system performance, but encrypting very large files or many files at once might cause slight slowdowns.

Conclusion

Using EFS is an easy way to add an extra layer of security to sensitive files on Windows. Encrypting files with EFS ensures that only your user account can access them. Make sure to back up your encryption key and understand EFS’s limitations.

If you share your account or computer with others, EFS may not be sufficient to protect your private files. In those cases, Wise Folder Hider can offer stronger protection by hiding, locking, and encrypting sensitive files.