I should really have known better than to plug a drive with one single TrueCrypt'ed partition into a PC prior to installing Windows 2k8 Server R2. What will happen is that the installer might randomly decide to place the MBR on that disk, overwriting the TrueCrypt header. I realized this after 5 hours of nursing the box to being completely patched, when I wanted to mount the drive with all my data. So. What can you do in this kind of scenario? You can read this post.