I wanted to overwrite my previously deleted files

[Saxon]

for extra security measures but when I go into disk utility and click on the Erase tab, the erase free space tab, and the others too, are unresponsive.

Any idea why? I would appreciated any advice on how to solve this issue.

 

[jafingi]

You're using the rMBP?

1) It would hurt your SSD to zero it out.
2) No need, since (when formatting an SSD) the encryption key is removed and replaced by a new key. Hence the data would be unreadable.

 

[Saxon]

Yes, it is a Retina.

In two weeks I will be working in a collaboration with some guys from another firm and I wanted to cover my bases to make sure that they couldn't get a hold of the drafts I'm currently working on. I'm 99% sure they wouldn't hack my laptop but I just want to be safe.

So you are telling me that once I empty my trash those files are unrecoverable via osx or an outside program. Is this correct?

 

[leman]

So you are telling me that once I empty my trash those files are unrecoverable via osx or an outside program. Is this correct?

Nope, they can still be recovered. There was a thread on SSD security few days ago, should be an interesting read for you: https://forums.macrumors.com/showthread.php?p=17172659#post17172659

 

[jafingi]

Yes, it is a Retina.

In two weeks I will be working in a collaboration with some guys from another firm and I wanted to cover my bases to make sure that they couldn't get a hold of the drafts I'm currently working on. I'm 99% sure they wouldn't hack my laptop but I just want to be safe.

So you are telling me that once I empty my trash those files are unrecoverable via osx or an outside program. Is this correct?

If you format you will be unable to recover the data on the SSD.

You can also enable FileVault which encrypts all data in real time, so only your password can be used to read files. You can enable it in Settings->Security.

If you just delete them from the trash, there is a possibility that someone can recover them. However, it is really almost impossible.

I have FileVault enabled on all my Macs. I like the feeling that no one can read my files, even if the Mac is stolen.

 

[ColdCase]

With file fault enabled, your biggest vulnerability will be the password. It may give you a false sense of security as when someone looks over your shoulder as you enter it... you have no security and may not realize it.

As far as making sure no one gets your current stuff you are deleting, the reformat works good enough.