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I am returning my MacBook Air to Apple and want to know the best way to ensure my data is not recoverable from the flash storage. I currently have Filevault 2 enabled, however before I enabled it I had already logged into eBay and a few other sites, and had already downloaded and logged into my password manager (Roboform Everywhere).

Will my passwords and any other data be recoverable if someone buys this machine as a refurb?

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Assuming you return it permanently (not for repairs), you could use some utility to simply wipe the disk. Why bother encrypting it and hoping nobody recovers it, when you can let it run a night on destroying the data entirely? Search something that securely wipes by the way, just hitting the delete button is not enough. –  Luc Oct 8 '12 at 15:56
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Notably missing from this question is whether your Macbook Air uses a HDD or SSD. This is a critical aspect of your question. (Also, @Luc: many SSDs support a full disk AES encryption, storing the private key to NVRAM. On a secure wipe, the private key is erased, a new is generated, and the remaining data is left inaccessible (unless the attacker somehow breaks AES or discovers the private key, which is unlikely). –  Moses Oct 8 '12 at 16:08
    
@Luc How to you securely wipe SSDs? –  rox0r Oct 8 '12 at 16:08
    
@Moses I mentioned it uses flash storage (it is not an actual 'drive'), this is a 2012 MacBook Air. –  Thomas Oct 8 '12 at 17:10
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@mgjk According to this post Macs do not support ATA security. –  sschuberth Jan 11 '13 at 14:14
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3 Answers

up vote 3 down vote accepted

Found this answer on Apple.StackExchange.com. Since you have a 2012 MacBook Air I will assume that you have Lion. If true and since you say that you are using FileVault 2, this procedure from this answer should work for you:

If your MacBook Air supports Lion Recovery Mode, and your using full disk encryption such as FileValut2 you will not need anything else to do it other than follow the steps below.

  1. Boot your MacBook Air into Recovery Mode by holding down Command+R while booting it.
  2. Open the Disk Utility Program, select the drive you want to securly erase.
  3. Select the "Erase" tab
  4. Click "Security Options..."
  5. Drag the slider to the Most Secure setting or some where in between and then select "OK"
  6. Then click "Erase..." and follow the remaining on screen prompts.

Note: For more information on how secure the Disk Utilities Secure Erase feature is see About Disk Utility's erase free space feature

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I'm actually using Mountain Lion (sorry, should have mentioned that earlier) but this worked nonetheless, thank you! –  Thomas Oct 9 '12 at 11:54
    
Forgot to mention: After step 2 I had to select the encrypted partition, click the blue 'unlock' option on the menu, and unlock with my password before the security options became available (they were greyed out). –  Thomas Oct 9 '12 at 12:05
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Probably just use Disk Utility, select disk, Erase.

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Can you do that on a running system? –  HeatfanJohn Oct 8 '12 at 19:02
    
Run it from USB or Firewire –  atdre Oct 9 '12 at 15:27
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Because of garbage collection flash storgage is extremely challenging, even for authorities, to recover data after it has been deleted.

The below are alternate methods to the above answers. I provide them because you have yet to mark them correct.

Delete critical file.

Boot from the install thumb drive that came with your mac.

Open disk utilities and 0 the disk.

This will be sufficient.

If your mac did not come with a thumb drive:

A) take your mac to apple and make them erase it in front of you

B) Install a mac os 10.6 or later on a 16GB thumb drive. Boot your mac from this and preform the above procedure.

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