I have a MacBook Pro with a separate user account for work-related stuff. Suppose I am required by contract to use reasonable means to destroy all copies of data that I had access to while performing the contract.
What is a reasonably secure way to wipe a single account off the machine so it's practically impossible to recover the data from that account? Is it sufficient to simply delete the account and its contents? (My laptop has an SSD and I presume the firmware's write optimizations make it more difficult to recover deleted data than on magnetic media.) If not, does it make any difference if I'm using FileVault? If that still isn't secure enough, then what about deleting the account, doing a full-backup of the remaining account(s), formatting the SSD, and restoring the backup? Presumably the backup would not include any data from the previously-deleted work account...right? Or is there some other recommended way to selectively wipe a user account on a Mac laptop?