Best way to securely wipe files?

[stanw]

I want to sell an iMac with an SSD and want to make sure that my files can not be retrieved. In the past I would simply use the security settings in Disk Utility to run a secure wipe, though I know you are not supposed to do that with SSD. Is there some other way to prevent files from being retrieved? OR is it not an issue with SSD drives after simply emptying the trash?

Thanks.

 

[maflynn]

Hard drives can have their data restored for a couple of reasons, first the data is not destroyed when deleting a file, its reference (location) on the drive is removed. Secondly, the magnetic attributes allow services to reconstruct files even if the file was overwritten.

SSDs do not use majestic but solid statement, the mechanics of SSDs mean when you wipe a drive, the data is gone.. There's no reason to do multiple formats and in fact you can decrease the lifespan by doing one of those high count erase procedures.

 

[stanw]

I understand that in theory, anything can be retrieved unless you destroy the drive...I'm not concerned on that level, I just want to know what level of formatting I can use to make it unrealistic for the average person or techie to retrieve my data. Are you saying that just emptying the trash, or doing a basic format of the SSD results in the data being gone/not likely retrievable on the SSD?

Thanks!

 

[DeltaMac]

I understand that in theory, anything can be retrieved unless you destroy the drive...I'm not concerned on that level, I just want to know what level of formatting I can use to make it unrealistic for the average person or techie to retrieve my data. Are you saying that just emptying the trash, or doing a basic format of the SSD results in the data being gone/not likely retrievable on the SSD?
...

Why not do both? Empty the trash, then erase the SSD and reinstall.
Or, another option is to prep for the erase first by enabling FileVault to encrypt the drive, then erase the encrypted volume.
No one can retrieve the data from an encrypted/erased volume, no matter how friendly you get with various 3-letter name organizations

 

[stanw]

1. By erasing the SSD, is this done by just rebooting while holding Command + R and going into disk utility and just choosing to erase the drive? OR is there another way to do this with an SSD?

2. After turning on File Vault in preferences, how do I erase the encrypted volume? Do you mean to simply turn on File Vault and than to perform the erase of the SSD as indicated in question #1?

Thanks!

 

[DeltaMac]

Command + R boots the Recovery partition on your boot drive.
Option+Command+R boots you to Apple's servers (Internet Recovery), where you have access to the same tools (Disk Utility), and from there you can install the same OS X system that your Mac originally shipped with (assuming your iMac is newer than 2010 models). The spinning globe is your key to realize that your Mac is booting from the network servers, and not from your drive. That means you can completely clear all partitions on the hard drive, if that's what you want to do.

If you decide to turn on FileVault, you have to wait until it is done.
Yes, the erase process is exactly the same, you are just erasing an encrypted volume. Erasing leaves you with an unrecoverable disk, and then reinstall with your choice of OS X, etc.

 

[CoastalOR]

OP: Don't forget to sign out of some services and deregister your Mac with Apple before you sell your iMac. BTW, +1 for using FileVault.
See What to do before selling or giving away your Mac