File Vault, which encrypts your main drive against determined attack, is so transparent that you really do not know it is working. It is a precaution any Mac user should take.
Simply protecting your computer with a password is merely the first step. It’s sensible, and recommended, but it will not stop a determined thief. All that is necessary is to remove the drive from the computer and access it independently. All your data is then laid out for prying eyes to devour.
File Vault effectively prevents this happening. Once turned on, it will work in the background and ensure that everything on your computer is safe.
The latest version, File Vault 2, offers full-disk encryption and, when the computer is powered off, the drive’s data is fully unrecoverable without a password. As a bonus, it will also let you use Find My Mac to completely wipe your drive remotely.
See this article in MacWorld and also take a look at the four security options everyone should know.
I strongly disagree with you. File Vault makes a drive much more likely to become unusable. I had it enabled for a few weeks before my computer crashed during a large read/write process. I lost all data from the drive but was eventually able to reformat it without encryption.
It’s interesting to hear your experiences and, perhaps, it should give prospective users food for thought. I agree that the early implementation of File Vault was buggy and unreliable. But I have been using File Vault for several years and currently it has been totally reliable. In fact, as I said in the article, it is easy to forget it is running at all. It’s frustrating, though, when things do go wrong and you have my sympathy.