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Article ID: 308993 - Last Review: December 21, 2007 - Revision: 2.2

This article was previously published under Q308993

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SUMMARY

This article describes how to decrypt a file that been encrypted by using Encrypting File System (EFS) in Windows XP.

Encryption is converting data into a format that cannot be read by other users. You can use EFS to automatically encrypt your data when it is stored on the hard disk.

Note Only the user who encrypts a file can recover data that has been encrypted, unless the user specifies a recovery agent before they encrypted the files. To make sure that you can decrypt files in the future, you should always export your certificate and private key and keep them in a safe location.

For more information about how to do this, click the following article number to view the article in the Microsoft Knowledge Base:
241201  (http://support.microsoft.com/kb/241201/ ) How to back up the recovery agent Encrypting File System (EFS) private key in Windows Server 2003, in Windows 2000, and in Windows XP

Advanced methods to decrypt a file or a folder

These methods are intended for advanced computer users. If you are not comfortable with advanced methods, you might want to ask someone for help or contact support. For information about how to contact support, visit the following Microsoft Web site:
http://support.microsoft.com/contactus/ (http://support.microsoft.com/contactus/)
To remove encryption from a file or a folder, use the appropriate method later in this section.

Method 1: Remove encryption from a file

Only the following people can decrypt an encrypted file:
  • The user who encrypted the file
  • Any user who was designated as a recovery agent before the file was encrypted
  • Any user who has the public key or private key for the recovery agent or the user who originally encrypted the file
  • Any user who has been granted access to the file
Members of the Administrators group cannot decrypt files unless the person who encrypted the files designated them as recovery agents before encrypting the files.

Note You must be the original user who encrypted the file or a designated recovery agent for the file to follow these steps. If you are not authorized to remove encryption, you receive the following error message:
Error Applying Attributes
An error occurred applying attributes to the file:

Path:\Filename

Access is denied
To remove encryption from a file, follow these steps:
  1. Use Windows Explorer to locate the encrypted file that you want to decrypt.
  2. Right-click the encrypted file, and then click Properties.
  3. On the General tab, click Advanced.
  4. Click to clear the Encrypt contents to secure data check box, click OK, and then click OK again.

Method 2: Remove encryption from a folder

Note You must be the original user who encrypted the folder or a designated recovery agent for the folder to follow these steps. If you are not authorized to remove encryption, you receive the following error message:
Error Applying Attributes
An error occurred applying attributes to the file:

Path:\Filename

Access is denied
To remove encryption from a folder, follow these steps:
  1. Use Windows Explorer to locate the encrypted folder that you want to decrypt.
  2. Right-click the folder, and then click Properties.
  3. On the General tab, click Advanced.
  4. Click to clear the Encrypt contents to secure data check box, click OK, and then click OK again.
  5. When you are prompted to confirm the attribute change:
    • If you want to decrypt only the folder, click Apply the changes to this folder only, and then click OK.
    • If you want to decrypt the folder and its subfolders and files, click Apply changes to this folder, subfolders and files, and then click OK.

MORE INFORMATION

For more information about how to use file encryption in Windows XP, click the following article numbers to view the articles in the Microsoft Knowledge Base:
307877  (http://support.microsoft.com/kb/307877/ ) How to encrypt a file in Windows XP
308989  (http://support.microsoft.com/kb/308989/ ) How to encrypt a folder in Windows XP
223316  (http://support.microsoft.com/kb/223316/ ) Best practices for the Encrypting File System

APPLIES TO
  • Microsoft Windows XP Professional
Keywords: 
kbexpertiseinter kbexpertisebeginner kbresolve kbhowtomaster KB308993
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