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How to erase SSD

hehe299792458

hehe299792458

macrumors 6502a
Original poster
Dec 13, 2008
772
3
I'd like to erase the SSD in my 2011 Macbook Air before I give it to a friend. I have purchased a copy of Lion in the App Store and burned the dmg to a USB drive. I have installed Lion on other machines by this way.

However, I can't seem to get the MacBook Air boot from the USB. So, I can't get to disk utility. How do I erase the SSD?
 
Hellhammer

Hellhammer

Moderator emeritus
Dec 10, 2008
22,164
582
Finland
Have you tried holding the alt button and then selecting the Lion DMG as the boot up volume? MBA boots so quickly so it may be hard to press it at the right time, so I usually keep tapping the alt key instead of just holding it.
 
D

deeddawg

macrumors G5
Jun 14, 2010
12,245
6,393
US
The Lion version in the App store is NOT suited for the 2011 Macbook Air. Different drivers or something. In time perhaps it will be, but for now the thing to do is use Lion Recovery to reformat and reload your system.

See http://support.apple.com/kb/HT4905 and http://support.apple.com/kb/HT4718

Boot holding down Command-R and be sure to have an Internet connection as you'll be pulling down about 3.5GB for a reinstall I believe.
 
hehe299792458

hehe299792458

macrumors 6502a
Original poster
Dec 13, 2008
772
3
deeddawg said:
The Lion version in the App store is NOT suited for the 2011 Macbook Air. Different drivers or something. In time perhaps it will be, but for now the thing to do is use Lion Recovery to reformat and reload your system.

See http://support.apple.com/kb/HT4905 and http://support.apple.com/kb/HT4718

Boot holding down Command-R and be sure to have an Internet connection as you'll be pulling down about 3.5GB for a reinstall I believe.
Click to expand...

It's fine with me if I download Lion again through the internet recovery mode. But what I need right now is to get to the disk utility on the Lion and secure erase my SSD. 7 pass, or something.
 
hehe299792458

hehe299792458

macrumors 6502a
Original poster
Dec 13, 2008
772
3
Hellhammer said:
Recovery mode includes Disk Utility.
Click to expand...

Thanks. It does indeed have disk utility.

However, it doesn't seem to have the secure erase options. Is there any way to secure erase my SSD? With a simple reformat, data can be quite easily recovered with a lot of software.
 
D

deeddawg

macrumors G5
Jun 14, 2010
12,245
6,393
US
Couple thoughts....

After all your files are deleted, copy a large data file (DVD image?) over and over to fill the SSD thereby overwriting any available blocks. Copy all files in folder A to new folder B, rename B and move it into A. Repeat. With a 2GB file, 7 or 8 iterations will fill the SSD.

Secure erasure on an SSD behaves differently than on a HDD due to wear-leveling. Also no real need to overwrite a block multiple times (and arguably it's better not to do so on an SSD).

Alternately, turn on FileVault such that the system is encrypted, then reboot / reformat / reinstall?
 
Last edited:
hehe299792458

hehe299792458

macrumors 6502a
Original poster
Dec 13, 2008
772
3
deeddawg said:
Couple thoughts....

After all your files are deleted, copy a large data file (DVD image?) over and over to fill the SSD thereby overwriting any available blocks. Copy all files in folder A to new folder B, rename B and move it into A. Repeat. With a 2GB file, 7 or 8 iterations will fill the SSD.

Secure erasure on an SSD behaves differently than on a HDD due to wear-leveling. Also no real need to overwrite a block multiple times (and arguably it's better not to do so on an SSD).

Alternately, turn on FileVault such that the system is encrypted, then reboot / reformat / reinstall?
Click to expand...

I already encrypted my data with filevault, and I filled up the SSD once with incompressible h264 files once. Is there anything else I should do to make sure that everything's gone forever?
 
Hellhammer

Hellhammer

Moderator emeritus
Dec 10, 2008
22,164
582
Finland
hehe299792458 said:
I already encrypted my data with filevault, and I filled up the SSD once with incompressible h264 files once. Is there anything else I should do to make sure that everything's gone forever?
Click to expand...

Well, the only way would be to drop the SSD into a can of corrosive acid and wait for the SSD to corrode. Or break the SSD in some other way.

Otherwise you are pretty much set with what you have done, the data should be irrecoverable.
 
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