Take Control of Security for Mac Users, Chapter 12: Recover from a Disaster
If you’ve lost data, or you’ve discovered malware on your Mac, or someone has stolen your personal information and applied for credit in your name, you need to take action to fix the problem as soon as possible. Regardless of the type of disaster, your first step is not to panic. Then you can methodically undo or repair the damage. Although the exact procedure will depend on your situation, this chapter contains some suggested general steps to get you started.