So the next best thing is to securely erase them. Of course, you can keep every hard drive and flash drive you’ve ever owned to reduce the chances of the above happening, but after a while this method starts taking up a lot of space. Also think of photos, videos, chats and again email contents that may include sensitive and personal content that can be used to blackmail you or destroy your reputation. Your browser history, auto-saved names and passwords in your browser, email contents, and sensitive documents like bank statements and tax returns, are all very valuable to someone who knows how to use it against you. Hackers are always looking for ways to get personal data to access bank accounts, to find user name / password pairs, that may be reused with other accounts, and to collect data to use in identity theft. Why is the data on your drive valuable to hackers? In this article, I’ll explain how to securely erase all sorts of drives: hard drives, flash drives, and SSDs.

Whenever you dispose of a Mac, or an external drive, you should securely erase it to ensure that no one can harvest data from it. If you use an external drive for, say, your music and video libraries, then this isn’t the case, but if you use an external drive for backups, there there’s lots of sensitive data on it. Your Mac’s drive is full of sensitive data: all your emails, contacts, private documents, and more. Your Mac, and any external drives you use, may contain important personal data. How To How to Securely Erase Data from Your Mac and External Drives

How to clean your macbook hard drive