Windows – Is it possible to mount a TrueCrypt volume to a NTFS mount point

This is very important! TrueCrypt system encryption partition DOESN'T CONTAIN TRUECRYPT HEADER. Non-system Truecrypt encrypted partition or file container contain header at first 128 blocks and backup copy at last 128 blocks of file/partition. So it's to impossible to decrypt systen encryption partition without backup header. Header of system partition is at the last block of hdd's first track. You can backup header:

dd if=/dev/sdx of=header.img bs=512 count=1 skip=62

If you want to access partition backup you have to clone partition to same size primary partition to different hdd and mark it as bootable. Then you have to restore header. First check if the first track is empty:

sfdisk -l /dev/sdy

If first partition strats at block 63 or more it's ok but if it's lower block number you can't continue. Restore your header

dd if=header.img of=/dev/sdy bs=512 count=1 seek=62

The you can access your backed up system partition using "Mount partition using system encryption without pre-boot authentication".

Theoretically you can convert Truecrypt system partition to standard Truecrypt parition or file container but you would have to chage some bytes in encrypted header. (decrypt header, change and encrypt again) http://www.truecrypt.org/docs/?s=volume-format-specification byte 124 and 252

Recovering the directory layout

I would recommend trying TestDisk, a free and open source tool that was designed to help recover broken filesystems and trashed boot sectors. Mount the drive in TrueCrypt first, and do all of your work on the decrypted drive.

It sounds like your best bet may be to try to recover the partition's MFT, or Master File Table (the rough equivalent of a Linux filesystem's superblock). A backup is stored; however, I don't know if a quick format erases the backup as well.

Getting individual files back

If the directory structure is toast, you may still be able to use an undelete tool such as Recuva, which is freeware, to recover your files. You won't get the directory structure, but if you have something really important you need back, you can sift through whatever Recuva finds.

Preventing this from happening

I bet I know how this happened... You plugged in the drive and Windows claimed that it wasn't formatted (because it is encrypted and looks like gibberish to Windows), and you accidentally let it. Regardless of whether or not this is what happened, this still really annoys me.

You need to prevent Windows from associating that partition with a drive letter, which will prevent it from trying to format it. With your disk plugged in (but not mounted in TrueCrypt), fire up the built-in Windows partition editor (hit Start, type partition, and choose "Create and format hard disk partitions"). Select your encrypted partition in the diagram, and right-click it and choose "Change Drive Letter and Paths." Remove all the letters associated with the partition, confirm, and you should be set!