Hi Niall, please could I have some help. I have used your wonderful guides which have been a lifesaver but I am now attempting to encrypt a Dell Latitude E6500 with BitLocker and I have followed your instructions and it works beautifully. The only problem I have is that Windows is now installed on the D drive. I have added the task sequence variable 'OSDPreserveDriveLetter'=false but this hasn't helped. I have a identical task sequence (minus bitlocker, TPM activation etc) which works fine but the BitLocker stuff seems to cause Windows to install on D. I'm so close to having this working but need some help please. Thanks!