It's my data and I'll open it if I want to... right? Errr.. not quite. If you've EFS encrypted files on Windows Vista you will not be able to open them under Windows XP. I'd thought I had most of my recovery scenarios covered. Was about to prep my XP Pro notebook for a trip and wanted to take some EFS secured data with me as well...
The following KB article applies...
Error message when you try to open an EFS-encrypted file in Windows XP or in Windows Server 2003 after the file has been opened in Windows Vista: "Access is denied"