Security & Privacy
You use hard drives or SSDs in your Macs, and hopefully you also use some drives to back up your data. Over time, some drives go bad and others get too small to replace them. You may be able to relocate old drives, but in some cases they have lived a good life and it's time to send them to the bucket.
But you can't just waste a hard drive or drop it off at a recycling center. These stations may contain personal information and you need to handle them carefully to ensure that no one can recover your information. That's how you do it.
To upgrade drives
You should have a backup of your Mac and all of your data. Ideally, use a combination of Apple's Time Machine and Intego Personal Backup to ensure all your data is backed up securely and redundantly. (Two backups are better than one.)
Over time, you get more data, especially if you have a growing media library and age. The 1 TB drive you bought a few years ago no longer holds all your music and movies, so you need a bigger drive. In some cases, you can still use the older drive for other backups, but as time goes by and you upgrade a few years, you have a collection of variable size drives that are not worth keeping.
I'm pretty careful about my data and my backups, and I usually replace my drives every three years or so. Statistics show that the error rate of hard drives increases significantly around that time, and it is often around when I find that I need more storage anyway. Your usage may vary, but with the low price of hard drives today and the need to ensure you don't lose data, it's probably a good time to look for replacements.
How to delete drives
Before proceeding, you should probably delete your drives. This article tells you how to do this with Disk Utility and how to safely delete free space from an SSD from the command line (using the Terminal app), since you cannot properly delete SSDs.
It is worth noting that if you've used FileVault or encrypted your drives with Mac, you probably don't have to worry about deleting them. As long as the password is complex enough that no one can figure it out, you can feel comfortable just taking the drives to a recycling center. But if you are still worried, or not encrypted the drives, or if you are not sure and they do not work, you should disassemble them.
How to disassemble hard disks
When I have a lot of old hard disks you want to get rid of, it's time to get some tools out and get to work. You need several obscure screwdrivers, so it's best to buy a set of computer equipment. I use a toolbox from iFixit and I have never encountered a screw that it doesn't have a head on.
Start by unscrewing each screw you find, especially on the aluminum cover of the disc. Some drives have a variety of different types of screws, and others use the same type. You may find some screws fixed, and you may need to resort to some other tools to separate parts of the disk. (Keep a good rope and a solid flat head screwdriver handy.) Here's a drive I took apart where I couldn't get all the screws off the cover, so I had to bend it with tongs:
Depending on the size at the stations, and their ages, the plates will be different. I recently destroyed some 2.5 "hard drives, and the plates were made of glass. For these drives you can just crush the plates. Be careful, the glass can be very sharp so goggles and gloves are recommended.
3.5" Hard disk drives is made of aluminum, with several coatings of different materials. For these discs, there are several ways to ensure that data cannot be restored. Depending on your tools, you can: suck them in acid scrape them all with a screwdriver sandblasting them with a multifunction tool (a grinding head) [demagnetize them with a very strong magnet]
It's best to plan ahead and use full-site encryption for all your drives so you don't have to worry about your data being available when you need to Get rid of them. Safe removal of the stations is a good idea, and as a last resort, they dismantle them and destroy the plates a good weekend project.
Related: How to enable FileVault Full Disk Encryption on Mac
How can I learn more?
We are discussing how to safely waste old drives on this week's edition of Intego Mac Podcast so be sure you subscribe to that you do not miss the last episode. You will also subscribe to our email newsletter and keep an eye on Mac Security Blog for updates.
About Kirk McElhearn
Kirk McElhearn writes about Macs, iPods, iTunes, books, music and more on his blog Kirkville.
He co-hosts Intego Mac Podcast and PhotoActive, and a regular contributor to The Mac Security Blog, TidBITS, and several other websites and publications.
Kirk has written more than twenty books, including Take Control Books on iTunes, LaunchBar and Scrivener.