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View Full Version : Help! Returning Macbook Air. Impossible to Securely Delete All Data?




VideoNewbie
Aug 6, 2012, 04:07 AM
I know this is covered extensively on google. instructions say to "Reboot the system while holding Command and R keys - that should boot you into the recovery partition"

But how can i do a secure erase ? the option for doing a 3 pass or 7 pass secure erase is greyed out. how can i do a secure erase on the macbook air? (2012 mbair mountain lion)

furthermore i found this article saying ssd might be impossible to securely erase unless you physically destroy the disc? http://www.informationweek.com/news/storage/data_protection/229219009?cid=RSSfeed_IWK_All


help!



ketchup4life06
Aug 6, 2012, 04:15 AM
Hey,
I do not have an answer to your question, but I have returned 2 Macbook Air's in the past and I always just re installed the OS and left out my personal information. If you call them up, they will tell you that it is unnecessary since once it arrives it is reformatted anyways, but paranoia gets to me sometimes as well. Anyways hope someone helps you!

zakdoc89
Aug 6, 2012, 04:22 AM
AFAIK you can't do a secure erase from the onboard partition.... You will need a recovery USB or CD and do it like that

KPOM
Aug 6, 2012, 05:32 AM
The best option is to encrypt the drive using FileVault 2 and then do a regular format. That would make it much more difficult for someone to retrieve your data.

Hawkeye16
Aug 6, 2012, 03:02 PM
Even doing encryption using the disk utility then erasing will make it difficult to get at what you erased. Not worth anyone's time unless you tell them differently.

VideoNewbie
Aug 6, 2012, 05:29 PM
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ok so far weve had 4 responses none of which really answer my question.
anybody else?

Beanoir
Aug 6, 2012, 05:35 PM
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ok so far weve had 4 responses none of which really answer my question.
anybody else?

You actually have the answer in your first post

minik
Aug 6, 2012, 06:07 PM
According to Apple (https://support.apple.com/kb/HT3680?viewlocale=en_US&locale=en_US)

Note: With OS X Lion and an SSD drive, Secure Erase and Erasing Free Space are not available in Disk Utility. These options are not needed for an SSD drive because a standard erase makes it difficult to recover data from an SSD.

For more security, consider turning on FileVault 2 encryption when you start using the SSD drive.

mayuka
Aug 7, 2012, 12:59 AM
IMHO there's a way. It should work with an USB-bootdisk. I haven't tried this.

http://www.anandtech.com/show/2738/11

KPOM
Aug 7, 2012, 06:04 AM
-

ok so far weve had 4 responses none of which really answer my question.
anybody else?

There's a reason traditional secure erase is disabled. First of all, it doesn't really work since an SSD controller won't allow the data to be completely re-written 3 or 7 times in exactly the same space. If it always allowed that, it would wear out the drive very quickly, and so it prevents it from doing so.

If your aim is to make the data unreadable, we have all given you a way to do it. Perhaps if you can boot into a Linux partition, there may be a way to run a SATA secure erase command, but note that the operation will take a very long time and it won't be easy to do and might brick the drive.

Jimf1234
Aug 7, 2012, 08:18 AM
If you have another Mac boot the air into target disk mode and wipe it from the other Mac. I've done this with other macs but never a air.

oneMadRssn
Aug 7, 2012, 08:21 AM
The reason those options are greyed out is because there no point in doing them on an SSD.

On a spinning disk hard-drive with a regular erase, the data is actually kept on the hard drive while the space is marked as "free" or "available" for later use. Hence, we have these secure erase methods of purposely overwriting those sectors 3 or 7 or whatever number of times to make sure it's unreadable.

On an SSD, once the data is erased it's gone forever. There is no recovering deleted data. Unlike on a spinning disk hard drive, there is no physical/mechanical medium to look back to. Therefore, overwriting it any number of times is useless.

Just format the drive, and that's it.

mayuka
Aug 7, 2012, 08:55 AM
Just format the drive, and that's it.

You should mention that a quick format just erases the partition table. The data is still there physically. Just use a hex editor on the device and you'll see the raw data. Only a complete erase will completely remove all data. Completely erasing more than 1 time is silly though.

h00ligan
Aug 9, 2012, 04:00 AM
Encrypt the drive with FileVault (random password) and then delete the partition. Problem solved.

dcorban
Aug 10, 2012, 09:06 AM
There should be no need for secure erase on Apple-supplied SSD. The native TRIM support ensures that the data is physically erased when the OS deletes it.

Blackberryroid
Aug 10, 2012, 09:10 AM
You should mention that a quick format just erases the partition table. The data is still there physically. Just use a hex editor on the device and you'll see the raw data. Only a complete erase will completely remove all data. Completely erasing more than 1 time is silly though.

If the data's still there, then what happens when you write new files? It wouldn't fit.

KPOM
Aug 10, 2012, 09:53 AM
If the data's still there, then what happens when you write new files? It wouldn't fit.

It overwrites it at that time. A quick format is like clearing the table of contents. It marks the entire drive as available to be written to. So even if there is data on 110 GB of a 120GB drive, it will accept a 20GB file because it will just overwrite space as necessary.

mayuka
Aug 10, 2012, 10:00 AM
If the data's still there, then what happens when you write new files? It wouldn't fit.

old data will be overwritten but until it is overwritten ist is still there physically.

VideoNewbie
Aug 19, 2012, 09:27 PM
Just format the drive, and that's it.


is there a correct way to format the drive? or do i just simply restart the computer while holding down command & r keys?

BigB82
Aug 19, 2012, 10:41 PM
I dont understand why people freak out, when you format from disk utility just the regular erase. its not like you have fbi stuff or csi stuff on the computer or that its going in the hands of a russian spy, someone would have to know what exactly what they are doing to want to go in a returned computer to retrieve stuff and have a reason to, im a very careful person but is it me or do people over react here?

VideoNewbie
Aug 20, 2012, 12:45 AM
is there a correct way to format the drive? or do i just simply restart the computer while holding down command & r keys?

same question as above...
also how many hours does this process take?

oneMadRssn
Aug 20, 2012, 08:22 AM
is there a correct way to format the drive? or do i just simply restart the computer while holding down command & r keys?

Yes. Boot using command-r, then launch disk utilities from the menu bar and erase the drive. Don't do the "quick" erase, just the regular one (I think it's called "zero out data").

To put it simply: if the disk get erased, then you did it right. There is no wrong way to format a drive.

h00ligan
Aug 21, 2012, 05:07 PM
Zeroing out a ssd is absolutely pointless.

Encrypt
The drive (which will take less time) using FileVault and then boot and delete the partition.

VideoNewbie
Aug 21, 2012, 05:51 PM
Zeroing out a ssd is absolutely pointless.

Encrypt
The drive (which will take less time) using FileVault and then boot and delete the partition.


what if i did an encrypted format? (too late to encrypt the drive didnt do that before erasing)

mayuka
Aug 22, 2012, 01:17 AM
what if i did an encrypted format? (too late to encrypt the drive didnt do that before erasing)

It could help to write random data to the SSD. the linux tool "badblocks" can do that. You'll have to compile it yourself, though it runs on OS X too.

stchman
Aug 22, 2012, 01:02 PM
From what I've read, data recovery is a completely different animal for solid state flash memory than a spinning hard disk. The way data is stored is the flash memory is manufacturer and controller dependent.

All in all data recovery for an SSD appears to be FAR more difficult than a traditional spinning HDD. It is HIGHLY unlikely that someone is going to go to all the effort to see the average Joe's BS on their computer.

With all this being said, where there is a will there is a way. While the Apple terminal does not have a shred command, the Trash has a secure delete option. Simply take all your data, move to Trash, and securely delete it.