Erasing MacBook Air

teknobrat2003 · Apr 11, 2012, 10:46 PM

I plan to sell my Macbook Air 2011 with lion. I used the disk utility nonsecure erase disk function which only took a couple seconds to erase the disk and then reinstalled lion via internet recovery. My question is, if I sell this to someone, can they easily recover the data from my harddrive which was erased using non secure erase?

bogatyr · Apr 11, 2012, 10:55 PM

Short answer: yes. The data isn't erased. If you want to erase it you need to do a secure erase - though I'm not sure how effective that is on an SSD. I was always told SSDs could choose to write data to different areas than specified for wear leveling.

teknobrat2003 · Apr 11, 2012, 11:00 PM

So then is it easy for someone to recover the data from my ssd in the macbook air then?

bcaslis · Apr 12, 2012, 04:27 PM

Quote:

Originally Posted by teknobrat2003

So then is it easy for someone to recover the data from my ssd in the macbook air then?

Theoretically yes. But some SSDs do their own housekeeping which makes it very bad to recover existing data. But Apple's own disk utility prevents secure erasing on the Apple SSDs so you don't have much choice in this.

unlimitedx · Apr 12, 2012, 04:56 PM

can iphone data be recovered by unscrupulous people too?

bogatyr · Apr 12, 2012, 06:52 PM

Quote:

Originally Posted by bcaslis

But Apple's own disk utility prevents secure erasing on the Apple SSDs so you don't have much choice in this.

The Apple disk utility let me do a secure erase on my MBA SSD.

bcaslis · Apr 12, 2012, 07:42 PM

Quote:

Originally Posted by bogatyr

The Apple disk utility let me do a secure erase on my MBA SSD.

Are you running Lion? It doesn't on 2011 models that come with Lion.

bogatyr · Apr 12, 2012, 08:26 PM

2011 refurb bought a couple weeks ago, came with Lion. Used it for a couple days and wiped it to reinstall. Wiped it from the recovery mode, 1 pass secure wipe.

If you select the drive from the tool, it's grayed out. If you select the partition, secure erase is available. Just double checked since you had me second guessing myself

bcaslis · Apr 13, 2012, 08:42 AM

Interesting. Doesn't work for me even when doing the same thing. Maybe it's dependent on which SSD is in the machine.

bogatyr · Apr 13, 2012, 08:46 AM

Quote:

Originally Posted by bcaslis

Interesting. Doesn't work for me even when doing the same thing. Maybe it's dependent on which SSD is in the machine.

I'm not sure if it even helps with an SSD anyways, since they can choose to write data wherever they want for wear leveling. I just figured I'd try it since I never thought an SSD could be secure erased.

tbaer · Jun 22, 2012, 04:26 PM

Here is a kb about it:
http://support.apple.com/kb/HT3294

Quote: "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 SSD because a standard erase makes it difficult to recover data from an SSD."

KPOM · Jun 22, 2012, 04:31 PM

Quote:

Originally Posted by teknobrat2003

So then is it easy for someone to recover the data from my ssd in the macbook air then?

What I've heard is that if the data was encrypted when it was first written (i.e. if you have FileVault2 active), that if you format the drive it would be very difficult for someone to recover data. If it is unencrypted, then it could be recovered a bit more easily from an SSD than a HDD since traditional wiping techniques don't work on SSDs.

dcorban · Jun 22, 2012, 06:12 PM

So much misinformation in this thread.

If you have an Apple supplied SSD with Lion (or Snow Leopard 1.6.8), then a regular erase is sufficient due to it supporting TRIM.

DVD9 · Jun 23, 2012, 02:27 PM

Quote:

Originally Posted by KPOM

What I've heard is that if the data was encrypted when it was first written (i.e. if you have FileVault2 active), that if you format the drive it would be very difficult for someone to recover data. If it is unencrypted, then it could be recovered a bit more easily from an SSD than a HDD since traditional wiping techniques don't work on SSDs.

This is the correct answer. Encrypt with Filevault2 before you start using the drive. Everything else with an SSD is a guess.

silverjam · Jun 30, 2012, 06:12 AM

I agree with the FileVault comments but for what it is worth I thought I would make the following comments relating to OSX Secure Erase options on SSDs

Mac users without SSDs keep suggesting SSD users (MBA for example) can secure erase via Disk Utilities or via Disk Utilities through the Recovery partition. You can't do that if you have the newer Macs. The option is greyed out. But there are easy ways to get around it. I should note though that secure erase through Disk Utility doesn't work properly on SSDs as it does on non-SSD drives. Google this and also see notes above. The whole issue of securely erasing SSD's and TRIM and Garbage Collection and the efficacy of overwriting is beyond my points I wish to make here, but is clearly a factor(if not the key factor) in the whole process.But anyway here's how you use OSX Secure Erase on SSDs if you really want to.

Option 1: You need a Recovery Partition USB Drive. It is like the current Recovery Partition on new Macs but it is on a thumb drive. Apple support has instructions or Google it. You boot into the RP thumb drive by pressing the Option key after start. Then in Disk Utility you format the SSD drive as Journaled Encrypted. Once it is formatted in this form you can then securely erase the free space which is the entire drive as you have just formatted it.

Option 2: Same as above up to the point you see the Disk Utility, Time Machine etc etc option screen. Launch Terminal from the Utilities Menu then use the "diskutil" command.

Enter "diskutil list" to find the disk/volume you want to erase (e.g. disk0 or disk0s2)

Enter "diskutil secureErase" to see the erase strength options.

Once you know what you want to do, as an example enter "diskutil secureErase 4 disk0" to erase the complete SSD drive of a MacBook Air to US DoE 3-pass standard.

It takes about 1.5 hours to do a three pass.

Does this fully Secure Erase an SSD? No. But it is better than nothing.

Just encrypt your drive to begin with.

Also you will need to do a full OSX install (or download if you have the newer Macs). I think you can erase freespace using diskutil but I have never tried this option.

Final note, I provide this info, not because it is a true secure erase of an SSD, but because so many people say you can just choose secure erase freespace or the drive when this is not true on the new Macs with SSDs!!! Apple has greyed the option out in the GUI format of Disk Utilites so you can only do it through the Terminal or if the drive is formatted HFS+ Encrypted.

Silver

KPOM · Jun 30, 2012, 07:10 AM

Quote:

Originally Posted by teknobrat2003

I plan to sell my Macbook Air 2011 with lion. I used the disk utility nonsecure erase disk function which only took a couple seconds to erase the disk and then reinstalled lion via internet recovery. My question is, if I sell this to someone, can they easily recover the data from my harddrive which was erased using non secure erase?

The best solution is to turn on FileVault2. Then you can reboot and erase the data. It may not be perfect, but it increases the odds that someone would be unable to recover old data.

hfg · Jun 30, 2012, 11:02 AM

I just encrypt the drive using FileVault (that takes awhile too). Once it completes, I do a standard install, performing a simple erase first. I would avoid any attempt to perform a multi pass secure erase on a SSD which might affect the performance for the new owner.

robvas · Jun 30, 2012, 11:24 AM

To be safe you can always do a fresh install. Then create some giant file (DVD ISO or something) and then just keep making copies of it until you fill the whole drive. Then delete them all.

silverjam · Jul 3, 2012, 04:46 AM

This worked for me. See other post.

http://forums.macrumors.com/showthread.php?t=1397264

Apr 11, 2012, 10:46 PM	#1
teknobrat2003 macrumors member Join Date: Mar 2011	Erasing MacBook Air I plan to sell my Macbook Air 2011 with lion. I used the disk utility nonsecure erase disk function which only took a couple seconds to erase the disk and then reinstalled lion via internet recovery. My question is, if I sell this to someone, can they easily recover the data from my harddrive which was erased using non secure erase?
	0

Apr 13, 2012, 08:42 AM	#9
bcaslis macrumors 68000 Join Date: Mar 2008	Interesting. Doesn't work for me even when doing the same thing. Maybe it's dependent on which SSD is in the machine. __________________ MacBook Pro Retina 13" 3.0GHz i7 8GB/512GB , iPad mini Verizon LTE 64GB, Mac mini server, iMac 24", iPhone 5 64GB
	0

Jun 22, 2012, 06:12 PM	#13
dcorban macrumors 6502a Join Date: Oct 2007	So much misinformation in this thread. If you have an Apple supplied SSD with Lion (or Snow Leopard 1.6.8), then a regular erase is sufficient due to it supporting TRIM. __________________ The Americans can always be trusted to do the right thing, once all other possibilities have been exhausted.
	1

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Apr 11, 2012, 10:55 PM	#2
bogatyr macrumors 65816 Join Date: Mar 2012	Short answer: yes. The data isn't erased. If you want to erase it you need to do a secure erase - though I'm not sure how effective that is on an SSD. I was always told SSDs could choose to write data to different areas than specified for wear leveling.
	0

Apr 11, 2012, 11:00 PM	#3
teknobrat2003 Thread Starter macrumors member Join Date: Mar 2011	So then is it easy for someone to recover the data from my ssd in the macbook air then?
	0

Apr 12, 2012, 04:56 PM	#5
unlimitedx macrumors 6502a Join Date: Jun 2010	can iphone data be recovered by unscrupulous people too?
	0

Apr 12, 2012, 08:26 PM	#8
bogatyr macrumors 65816 Join Date: Mar 2012	2011 refurb bought a couple weeks ago, came with Lion. Used it for a couple days and wiped it to reinstall. Wiped it from the recovery mode, 1 pass secure wipe. If you select the drive from the tool, it's grayed out. If you select the partition, secure erase is available. Just double checked since you had me second guessing myself
	0

Jun 22, 2012, 04:26 PM	#11
tbaer macrumors newbie Join Date: Mar 2012	Here is a kb about it: http://support.apple.com/kb/HT3294 Quote: "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 SSD because a standard erase makes it difficult to recover data from an SSD."
	0

Jun 30, 2012, 06:12 AM	#15
silverjam macrumors regular Join Date: Apr 2012	I agree with the FileVault comments but for what it is worth I thought I would make the following comments relating to OSX Secure Erase options on SSDs Mac users without SSDs keep suggesting SSD users (MBA for example) can secure erase via Disk Utilities or via Disk Utilities through the Recovery partition. You can't do that if you have the newer Macs. The option is greyed out. But there are easy ways to get around it. I should note though that secure erase through Disk Utility doesn't work properly on SSDs as it does on non-SSD drives. Google this and also see notes above. The whole issue of securely erasing SSD's and TRIM and Garbage Collection and the efficacy of overwriting is beyond my points I wish to make here, but is clearly a factor(if not the key factor) in the whole process.But anyway here's how you use OSX Secure Erase on SSDs if you really want to. Option 1: You need a Recovery Partition USB Drive. It is like the current Recovery Partition on new Macs but it is on a thumb drive. Apple support has instructions or Google it. You boot into the RP thumb drive by pressing the Option key after start. Then in Disk Utility you format the SSD drive as Journaled Encrypted. Once it is formatted in this form you can then securely erase the free space which is the entire drive as you have just formatted it. Option 2: Same as above up to the point you see the Disk Utility, Time Machine etc etc option screen. Launch Terminal from the Utilities Menu then use the "diskutil" command. Enter "diskutil list" to find the disk/volume you want to erase (e.g. disk0 or disk0s2) Enter "diskutil secureErase" to see the erase strength options. Once you know what you want to do, as an example enter "diskutil secureErase 4 disk0" to erase the complete SSD drive of a MacBook Air to US DoE 3-pass standard. It takes about 1.5 hours to do a three pass. Does this fully Secure Erase an SSD? No. But it is better than nothing. Just encrypt your drive to begin with. Also you will need to do a full OSX install (or download if you have the newer Macs). I think you can erase freespace using diskutil but I have never tried this option. Final note, I provide this info, not because it is a true secure erase of an SSD, but because so many people say you can just choose secure erase freespace or the drive when this is not true on the new Macs with SSDs!!! Apple has greyed the option out in the GUI format of Disk Utilites so you can only do it through the Terminal or if the drive is formatted HFS+ Encrypted. Silver
	0

Jun 30, 2012, 11:02 AM	#17
hfg macrumors 68000 Join Date: Dec 2006 Location: Cedar Rapids, IA.	I just encrypt the drive using FileVault (that takes awhile too). Once it completes, I do a standard install, performing a simple erase first. I would avoid any attempt to perform a multi pass secure erase on a SSD which might affect the performance for the new owner.
	0

Jun 30, 2012, 11:24 AM	#18
robvas macrumors 65816 Join Date: Mar 2009 Location: USA	To be safe you can always do a fresh install. Then create some giant file (DVD ISO or something) and then just keep making copies of it until you fill the whole drive. Then delete them all.
	0

Jul 3, 2012, 04:46 AM	#19
silverjam macrumors regular Join Date: Apr 2012	This worked for me. See other post. http://forums.macrumors.com/showthread.php?t=1397264
	0