Somewhat complicated scenario here, so im trying to describe it as simply as possible. Win7 (Pro and higher) allows mirroring of volumes/drives. Its sort of a (Software-) RAID1, with the advantage that an irreplacable controllercard/chipset can never become an issue. (Data always accessible.) In effect this means that Windows would 'unify' 2 different volumes under 1 single drive letter. Example: Partition1 on DriveA and Partition1 on DriveB would become one logical unit under drive letter D:\ TrueCrypt however (at least normally) expects each encrypted volume to be mounted separately under its own drive letter. In other words i cannot mount Partition1 on DriveB under D:\ when i already gave D:\ to Partition1 on DriveA. (Since the letter would no longer be available.) As a result i could always only mount one of the two involved volumes as D:\ , namely either that on DriveA or that on DriveB. This in turn would mean that as far as TrueCrypt is concerned, one of the involved volumes (either the main or the mirror) always had to be left unmounted. (Since using another drive letter would interfere with the mirroring.) But if a TrueCrypt volume is not mounted (meaning unlocked via password) you cannot write/read any data to/from it either. (Obviously.) Im sure you see the dilemma. Two volumes, one drive letter, and a program that expects each volume to have its own drive letter. Hence my question; has anyone ever tried this particular constellation of Win7 mirroring plus TrueCrypt? Would the encryption/decryption process, (due to the fact that the two volumes are mirrored through the operating system), be applied to both involved volumes even though only one of them is actually mounted in TrueCrypt? This would be very important for me to know, because i intend to mirror the four 500GB partitions of my new 'main'* drive 1:1 onto a second identical drive. (You know, to be on the safe side. After all 2.000 GB is not peanuts anymore.) But i need the encryption to work, otherwise i need not give this option any further thought. Thanks in advance for any clarifications. *There will be no OS on these volumes, its data storage only.