You didn't follow the correct procedure when you mounted the drive you ran Eraser on. If you had followed the correct procedure, it would not be possible to damage the hidden volume.When you mount your 'encrypted volume' (as opposed to what is referred to as a 'hidden volume' which resides undectably within an encrypted volume), click on [Mount Options] and in the window that pops up, check the option [Protect hidden volume against damage caused by writing to outer volume] and enter the passphrase for the hidden volume - it needs this to determine the boundaries of the hidden volume.If an attempt is made to write to the protected portion of the disk, the complete disk is automatically write-protected to safeguard the hidden volume and ensure plausible deniability.This is why you MUST ALWAYS select the option to protect the hidden drive when mounting your encrypted drive. If you don't, a random system file write anywhere on the disk could wipe out some data, or your complete hidden volume if it overwrites the hidden volume header. Go through the docs at trucrypt until you understand them completely, starting with www.truecrypt.org/docs/?s=hidden-volume-protectionIn the future rather than moving files and then erasing the free space, copy the files to the new location, and then securly delete the old files AFTER you have confirmed the integrity of the new copies. If you make a habit of always doing this, all the free space on your disk will never have any leftover data on it, and you will never lose valuable data if your computer has a hiccup during a 'secure move'.Everyone who has played with TrueCrypt and/or PGP has either deleted stuff they were trying to keep, or encrypted stuff so that nobody, including themselves, could ever recover it. It's all part of the learning process, and it sounds like you got off lightly this time.