Forget about the stupid hard drive. This stuff can be found on backups of the email server. COME ON!
E-mail’s do not reside on the desktop or laptop computer. They reside on the e-mail server, which may be a cluster of servers for fault-tolerance. The several hard drives arranged in an array that spreads the data out among all the drives with a “parity” bit to rebuild the drive in case of failure. If a drive fails, a spare drive takes over and the data is “rebuilt” from that “parity” bit and recovery algorithm. The probability of complete loss of data is next to zero unless the server and drive is incinerated.
On top of all that, the e-mail data is incrementally backed-up to tape most likely on a daily basis. And, a full back-up every week. Common criminals.