Question submitted by a reader of the blog:
Hello Tysa, I have an old Mac machine which runs extremely slow. I’ve just ordered a new Mac from the Apple Store. Now I want to sell my old Mac on eBay. I read that one of the best practices is to erase the hard drive so no one can retrieve any data from it. The thing is how to do this without the system restore CD?
Here’s my reply:
For modern Mac machines, you don’t need to rely on the original system disc to wipe a Mac clean. Plus, Macs shipped after OS X Lion don’t come with CDs any more (see this MacWorld news). So, there is no way you can get one unless your Mac really shows its age.
That said, you can quickly erase your old Mac hard drive with OS X’s Recovery feature, which is built into Apple’s Disk Utility. See this screenshot on my Mac. There is an “Erase” option. Note: it’s grayed out because I can’t erase the main hard drive when I turn on my Mac. You’ll have to shut down your Mac and use the trick below to access Disk Utility without booting the disk.
How to access Disk Utility on startup?
All you have to do is shut down your Mac, press the Start button, and hold Command + R keys (or Option key, depending on the OS X your Mac is with). It’ll come to a screen called “OS X Utilities”, there you’ll find Disk Utility, click it and erase your Mac securely.
This YouTube video made by Shani Jaf nails it step by step
In case you find the above method too complicated or it doesn’t work, another way is to use third-party software.
Reminder: using the above methods will permanently remove all data saved on the hard drive, use with caution. Before you proceed, make sure you’ve already backed up all important data to an external hard drive or cloud storage.