Someone enabled the encryption attribute on the folder that contains those
files. By default in Windows XP Pro only the owner of those files who put
the files in the folder will be able to decrypt them assuming the user's EFS
certificate/private key is on the computer. You can use the user certmgr.msc
to view your "user" certificates by looking in the personal\certificates
folder where you should see one that shows encrypted file system as the
intended purpose and says that "you have a private key that corresponds to
this certificate" on the general page of the certificate if you have ever
encrypted any files. You might want to logon as any other user account that
are on the computer too see if they work and you can use the support tool
efsinfo to show the name of the user than can decrypt the files if they have
their certificate/private key. Support tools are on the install disk in the
support/tools folder where you have to run the setup program there to
install them.
On a workstation computer if the user for those EFS files has ever had his
password "reset" then he will be denied access to the EFS files unless he
changes his password back to what to was before it was reset. Password
changes are done by the user using control-alt-delete or when prompted to by
the operating system. Passwords are reset by an administrator and a warning
message will appear telling them that doing such can prevent the user from
accessing their files. Reinstalling the operating system that involves
formatting the system drive is another common reason for users not being
able to access their EFS files. --- Steve
http://support.microsoft.com/default.aspx?scid=kb;en-us;243026&sd=tech ---
efsinfo use.
http://support.microsoft.com/kb/223316/ --- EFS best practices.