A reader wrote in to ask for an easy and safe way to get rid of her old Mac computers. She was worried that someone would be able to retrieve her hard drive after she discards the machines.
Deputy Tech Editor Trevor Tan answers.
Unfortunately, there is no easy way.
The easiest and also the best way to make sure your data is secure and unretrievable is to use a hammer and physically destroy the hard drive of your computer.
Once your hard drive is smashed into smithereens, no one will be able to connect to the hard drive and access any data in it.
If you are not into violence, you can always use the more tedious software method.
Assuming your Mac computers are running Mac OS X (and not the older Mac OS 8 or 9) and using conventional hard disk drives (and not solid-state drives), start up the computer while holding the Command and R keys. It will boot up to Recovery Mode.
Here, you will be given options to restore from the Time Machine Backup, Reinstall Mac OS, Get Help Online and Disk Utility. The last option is the one to note.
Click on Disk Utility, and click on the hard drive of your computer. Next, click on the Erase option.
In the next window, click on Security Options at the bottom left corner.
In Security Options, there is a slider that specifies how you might want to erase the hard drive.
Drag the slider to the Most Secure option, which indicates that it meets the US military standard of securely erasing magnetic media (see photo).
This option essentially erases the data in your hard drive and writes random "zeroes" and "ones" over it. This makes it impossible for hackers to retrieve previous data written on it.
The downside is that this process usually takes an awfully long time - up to seven hours or more, based on my experience.
If you're comfortable with it, choose this Most Secure Option, click OK, then click Erase.
Wait for the format process to finish and you can give your Mac computers to your friends or drop them off at recycling stations without fear of your data being retrieved.
