Filevault and Selling Computer

[machappyboy]

I'm selling my MacAir. Did not have Filevault turned on. Erased HD and reinstalled Sierra.

Can I now turn Filevault on, reerase the HD, reinstall Sierra, then turn it off for the sale? I will definitively erase all data from when I was using the machin?

 

[fischersd]

I'm selling my MacAir. Did not have Filevault turned on. Erased HD and reinstalled Sierra.

Can I now turn Filevault on, reerase the HD, reinstall Sierra, then turn it off for the sale? I will definitively erase all data from when I was using the machin?

That will likely take considerably more time than grabbing one of the utilities for doing random fills of hard drives to expunge your data securely, then formatting and reloading MacOS on the new volume.

A bunch of them reviewed here (most you make bootable media to use them):
https://www.lifewire.com/free-data-destruction-software-programs-2626174

 

[machappyboy]

This is an SSD...

 

[fischersd]

This is an SSD...

Whoops! Yep, you can't zero-fill it then.
There's a good how-to article on using filevault to securely erase your SSD here:

https://www.backblaze.com/blog/securely-erase-mac-ssd/

 

[Weaselboy]

Can I now turn Filevault on, reerase the HD, reinstall Sierra, then turn it off for the sale? I will definitively erase all data from when I was using the machin?

Yes. There is a small chance bits of old data would be on an area of the disk outside the FV volume, but the odds are low and that data would be very difficult for anybody to recover.

 

[hallux]

If you turn on FileVault then erase the drive and re-install the OS there is no reason to go in and turn it back off.

 

[machappyboy]

I turned on filevault, erased the disk imagine, but when I used command+R to reboot, only the internet recovery mode was available. Why can't I install Sierra from the recovery partition?

 

[Weaselboy]

I turned on filevault, erased the disk imagine, but when I used command+R to reboot, only the internet recovery mode was available. Why can't I install Sierra from the recovery partition?

How did you erase the drive?

It sounds like you erased the entire disk, including the recovery partition, leaving you only with Internet recovery.

 

[machappyboy]

I erased the 500 GB drive. I tried to erase the "sub disk" I forget what the name was.... but could click it. How should I have clicked it?

 

[Weaselboy]

I erased the 500 GB drive. I tried to erase the "sub disk" I forget what the name was.... but could click it. How should I have clicked it?

I'm still not clear how you were booted when you did this?

What you should have done was command-r boot to the recovery partition, then run the command below in Terminal to blow off the FileVault image, then erase the OS volume, then install the OS.

diskutil cs delete "Macintosh HD"

It sounds like perhaps you were in Internet recovery and erased the entire disk, which would wipe the recovery partition also.