Selling 2011 MacBook Air: Wiping SSD / Info

[Eggtastic]

Alright So I researched as best as possible on this as there are several ways to go about this. I have a 2011 11" MBA and I guess from what people have said I was able to boot using command+option+R. This brought me to internet boot (I forget what it was called), and I was able to wipe the SSD from there. Now everything seems to be good to go, the MBA starts up as if I bought it brand new with the set up screen.

My big question is, how effective was this wipe? I did the most basic option which didn't take much time at all. I just don't want some computer genius buying this machine and using it to gain access to my info (far fetched thinking, but just want to be safe). Was there a better, safer way about wiping my SSD or do you think I am fine to go ahead and sell this?

 

[KALLT]

It is a bit of a mystery what exactly happens when an Apple SSD is erased. macOS does support TRIM and there is some evidence that it is used when erasing a drive. However, it is not certain how the drive uses this.

You should have used file-system encryption. At this point, all you can really do is minimise the data on it. You can open a Terminal window in Recovery, find out the disk identifier and then perform a secure erase on the disk to write lots of useless data to it. This will cause unnecessary write operations and it is no guarantee that all data is gone.

diskutil secureerase 0 diskX

You can find the disk identifier with

diskutil list

There are also special programs that you can use to erase SSDs. One such program is Paragon Disk Wiper (freeware).

 

[garirry]

The only things that you should have done - if you haven't already, is deauthorize your computer from iTunes and sign out from all iCloud-related services. That's basically what Apple suggests you to do, then just like you've already done, reinstalling the OS from Internet recovery and erasing the storage device in the process. I suggest you read this: https://support.apple.com/en-ca/HT201065

As for security, if you've used FireVault, then I'd argue that there's nothing to worry about, as whoever gets access to your storage device (if they want to for whatever reason), they won't be able to access anything no matter how hard they try. If you didn't use encryption, I suggest you do a secure erase, basically follow the post above for that.