How to make sure MacBook is cleared/reset?

hieveryone

Hi all,

I have a 2012 MacBook Air running Catalina OiS. I followed steps found online to clear/factory reset it and re-install Catalina which seemed to go well, when I booted it up it had the 'choose language' screen and so I assumed it was 'box-fresh'. 

I gave the laptop away (it still works absolutely brilliantly) - but when it has been through the set up guide, it comes up with a user box and password (mine). 

What did I do wrong to not clear it properly? And how can I make sure there's no data of mine on it for the new user? 

Thanks

tempus_fugit

Without knowing what steps you went through its hard to say. It may be that you didn't log out of everything that you should have as per these instructions https://support.apple.com/en-gb/HT201065 before you erased the device. 

The official instructions from Apple to correctly erase a MacBook and reinstall the OS are here https://support.apple.com/en-gb/guide/mac-help/mh27903/mac, and I guess you would have needed to use the instructions under "On and Intel-based Mac without the Apple T2 security chip".

If you followed the instructions correctly and erased the disk before reinstalling MacOS, then there shouldn't be any of your data on there. Although I do remember vaguely from doing this myself a few years ago that there were different reformatting options giving different levels of security. I used an option that made sure every bit of data was overwritten, although it did take some time to complete.