No access to encrypted files after reinstallation of Windows XP

  • Thread starter Thread starter William Zeng
  • Start date Start date
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William Zeng

I was hacked by a virus recently. I formated my C: and reinstalled Windows
XP. Eventhough I used the same user name and password, I failed to get
access to previouly encrypted files and folders using XP's EFS. Any one can
tell me how this happen and how to resolve this problem. Thank you.
 
Before you encrypt anything important, you should back up your
personal encryption certificate (with its associated private key)
and the recovery agent certificate to a floppy disk and store it in
a secure location. If you ever lose your original certificate
(because of a hard disk failure, for example), you can restore
the backup copy and regain access to your files. If you lose all
copies of your certificate (and no recovery agent certificates exist),
you won't be able to use your encrypted files. No back door exists,
nor is there any practical way to hack these files.
(If there were, it wouldn't be very good encryption.)

HOW TO: Remove File Encryption in Windows XP
http://support.microsoft.com/default.aspx?scid=kb;EN-US;308993

Without a backup of the original Encryption Certificate Key, encrypted files
are unrecoverable as they will stay encrypted forever. There is no recovery
method since the encryption algorithm is now completely different with a
reinstall of Windows XP.

See if the following articles help in any way:

HOW TO: Take Ownership of a File or Folder in Windows XP
http://support.microsoft.com/default.aspx?scid=kb;en-us;308421

Best Practices for the Encrypting File System
http://support.microsoft.com/default.aspx?scid=kb;en-us;223316

Encrypting File System in Windows XP
http://www.microsoft.com/technet/tr...chnet/prodtechnol/winxppro/deploy/CryptFS.asp

EFS Files Appear Corrupted When You Open Them
http://support.microsoft.com/default.aspx?scid=kb;en-us;329741

Possible third-party solution:

Advanced EFS Data Recovery 1.30
http://www.softempire.com/advanced-efs-data-recovery.html

--
Carey Frisch
Microsoft MVP
Windows XP - Shell/User

Be Smart! Protect your PC!
http://www.microsoft.com/security/protect/

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|I was hacked by a virus recently. I formated my C: and reinstalled Windows
| XP. Eventhough I used the same user name and password, I failed to get
| access to previouly encrypted files and folders using XP's EFS. Any one can
| tell me how this happen and how to resolve this problem. Thank you.
 
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