A folder must be on NTFS to be encrypted using EFS.
Log files The encrypting file system EFS Disk quotas
Encrypting File System (EFS)
EFS stands for Encrypted File System and is used to encrypt folders and files in Windows XP or Vista.This encryption works ONLY when using the Windows NTFS file system!
Microsoft EFS stands for Encryption File System. This is used when you want to encrypt and protect your data and personal information from others by using a password.
Encrypting File System (EFS)
EFS Encrypting File System
see http://support.microsoft.com/kb/941674
Found on the ScanState Syntax document at microsoft docs site."Causes the ScanState command to copy the files in the encrypted format. The files will be inaccessible on the destination computer until the EFS certificates are migrated. EFS certificates will be automatically migrated; however, by default USMT fails if an encrypted file is found, unless you specify an /efs option. Therefore you should specify the /efs:copyraw option with the ScanState command to migrate the encrypted file. Then, when you run the LoadState command, the encrypted file and the EFS certificate will be automatically migrated.For example:ScanState /i:migdocs.xml /i:migapp.xml \server\share\migration\mystore /efs:copyrawImportantAll files must be encrypted if the parent folder is encrypted. If the encryption attribute on a file inside an encrypted folder has been removed, the file will be encrypted during the migration using the credentials of the account used to run the LoadState tool. For more information, see Migrate EFS Files and Certificates."
New Technology File System (NTFS) and High Performance File System (HPFS),NTFS supersedes the FAT file system as the preferred file system for Microsoft's Windows operating systems. NTFS has several improvements over FAT and HPFS (High Performance File System) such as improved support for metadata and the use of advanced data structures to improve performance, reliability, and disk space utilization, plus additional extensions such as security access control lists (ACL) and file system journaling. NTFS v3.0 includes several new features over its predecessors: sparse file support, disk usage quotas, reparse points, distributed link tracking, and file-level encryption, also known as the Encrypting File System (EFS).
enabling the EFS Recovery Agent template
The NTFS file system will allow you to use the full capabilities of Windows XP. For example. EFS (encrypted file system) will only work on an NTFS partition. However, if you have upgraded from a previous version of Windows to Windows XP it is likely that your file system will be FAT32. If you have a dual boot computer, using a previous version of windows or a Linux installation and intend on accessing some of your files from both operating systems, you will need to use FAT32 as older versions of Windows and Linux cannot read NTFS.