Não. O tamanho do bloco TrueCrypt é de apenas 16 bytes - esse é o tamanho mínimo que ficará inutilizável. Supondo que sua corrupção é limitada no escopo, você deve recuperar a maioria dos seus dados. Da FAQ do TrueCrypt :
What will happen when a part of a TrueCrypt volume becomes corrupted?
In encrypted data, one corrupted bit usually corrupts the whole
ciphertext block in which it occurred. The ciphertext block size used
by TrueCrypt is 16 bytes (i.e., 128 bits). The mode of operation used
by TrueCrypt ensures that if data corruption occurs within a block,
the remaining blocks are not affected. See also the question 'What do
I do when the encrypted filesystem on my TrueCrypt volume is
corrupted?
What do I do when the encrypted filesystem on my TrueCrypt volume is corrupted?
File system within a TrueCrypt volume may become corrupted in the same
way as any normal unencrypted file system. When that happens, you can
use filesystem repair tools supplied with your operating system to fix
it. In Windows, it is the 'chkdsk' tool. TrueCrypt provides an easy
way to use this tool on a TrueCrypt volume: Right-click the mounted
volume in the main TrueCrypt window (in the drive list) and from the
context menu select 'Repair Filesystem'.