I would expect a TrueCrypt volume to be fragile when it suffers from data corruption. This could happen for example because the hard disk, CD or DVD start to deteriorate, or when an USB stick is unplugged while a write is in progress.
On the TrueCrypt FAQ it is mentioned that this problem is limited because the data is encrypted in blocks of 16 bytes. However, I'dd like to know if this really so in practice. Is there anyone who has experienced severe data loss due to only small corruptions?