You cannot restore encrypted files to a remote computer in Windows 2000

On a computer that is running Microsoft Windows 2000, you successfully back up encrypted files from a remote computer. When you try to restore the files to the remote computer, the restore operation cannot restore some of the files. You may receive an error message that is similar to the following:

This problem occurs when all the following conditions are true:

• You try to restore the encrypted files to a remote computer.
• The file path of an encrypted file is longer than 260 characters.
• The Encrypting File System (EFS) backup API uses the OpenEncryptedFileRawW function to open a file that has the "\\?\" prefix. For example, the OpenEncryptedFileRawW function makes a call to open the file \\?\drive_letter:\subdirectories\file_name or the file \\?\UNC\server_name\share_name\subdirectories\file_name.

The "\\?\" prefix permits file paths that are longer than the 260 character limit that is set by the MAX_PATH variable. When you back up an encrypted file that has a path that is longer than 260 characters, the "\\?\" encoding works successfully. However, when the EFS backup API tries to open the same file for a restore operation, the API returns the ERROR_PATH_NOT_FOUND error status. This problem occurs because the "\\?\" or the "\\?\UNC" encoding is prematurely removed, and the computer receives the long file path without the "\\?\" or the "\\?\UNC" prefix.

To resolve this problem, obtain the latest service pack for Windows 2000. For additional information, click the following article number to view the article in the Microsoft Knowledge Base:

To work around this problem, make sure that the lengths of the file path names are not greater than the limit that is set by the MAX_PATH variable.

Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section of this article. This problem was first corrected in Windows 2000 Service Pack 4.