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I have erased and overwritten ssd on mb air - can this damage it?

I have encrypted my mb air 2011 , Then used erase free space x 3 then erase x 1 o/w. Now I can't seem to set up a new partition - but was able to select the drive and unlock it when reinstling osx.Is this allOK to continue?N cud hav i damgd the ssd?

MacBook Air, Mac OS X (10.7.5)

Posted on Jun 30, 2015 6:07 AM

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Posted on Jun 30, 2015 7:22 AM

It is unlikely you damaged your SSD, but you did reduce its life a little bit. SSD's have a limited number of writes per sector. The SSD includes spares, and rotates physical sectors into logical locations (the operating system only sees the logical sectors) to ware level the number of writes to any given physical sector. But once a physical sector has been stopped holding data, it is taken out of the rotation and you have one less spare.


erasing free space or overwriting large chunks of the SSD will insure that a large percentage of the physical sectors wear just a little be more. If you do this a lot, then you will eventually wear out more and more sectors until you have no spares and your SSD starts to loose capacity and die.


Just doing the erase free space once, will be OK in the long run, but I strongly suggest against doing it any more.


If you are worried about previous file data in the free space, then use System Preferences -> Security -> FileVault whole disk encryption. Then when you delete a file, the free space is still encrypted data that is useless to anyone getting your SSD.

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Jun 30, 2015 7:22 AM in response to Hello-91

It is unlikely you damaged your SSD, but you did reduce its life a little bit. SSD's have a limited number of writes per sector. The SSD includes spares, and rotates physical sectors into logical locations (the operating system only sees the logical sectors) to ware level the number of writes to any given physical sector. But once a physical sector has been stopped holding data, it is taken out of the rotation and you have one less spare.


erasing free space or overwriting large chunks of the SSD will insure that a large percentage of the physical sectors wear just a little be more. If you do this a lot, then you will eventually wear out more and more sectors until you have no spares and your SSD starts to loose capacity and die.


Just doing the erase free space once, will be OK in the long run, but I strongly suggest against doing it any more.


If you are worried about previous file data in the free space, then use System Preferences -> Security -> FileVault whole disk encryption. Then when you delete a file, the free space is still encrypted data that is useless to anyone getting your SSD.

Jun 30, 2015 3:34 PM in response to BobHarris

Thanks for the reply.

i reinstalled os x but now cannot access the computer. When I restart it spends some time loading with Apple logo On screen but then a no access symbol appears - circle with a line Through it.

when in disk utility on the left side there is an option - "Mac 0SX base system". I think I may have started up into this disk and from my understanding is not correct.

once before I had removed the main partition and then had to create another one - however this is all grey now. The message is :"

"Disk Utility cannot modify this disk because it contains CoreStorage physical volumes. Use command line diskutil instead."


Followed by this:


"This partition can't be modified because it contains encrypted partitions."


how can I create another partition. i can't get into the MacBook to run command line - BUT I barely know anything about that anyhow.

what what has to be done to get the laptop reasy to sell????

I have erased and overwritten ssd on mb air - can this damage it?

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