When you write random data to the disk, you will also destroy the boot mount (that little partition that is not encrypted so you can boot the PC and show the pa

When you write random data to the disk, you will also destroy the boot mount (that little partition that is not encrypted so you can boot the PC and show the password dialog). If you don't overwrite this partition, they police might believe that there is actual data on that disk. And I don't see any reason why you would not erase that part. Furthermore, if the encrypted AES keys are not stored in that boot partition, and you overwrite them, the algorithm might detect that the keys are corrupted and refuse to decrypt them with the given password. This once happened to me when a disk failed and corrupted the section where these keys were apparently stored. I don't know how truecrypte (the software used to encrypt the hard drive) handles drive encryption, though, so my information might not be accurate.