PDA

View Full Version : Clearing up computer for sale




cheddar-caveman
Apr 8, 2013, 02:10 AM
I am shortly going to sell my Air and will need to put it back to where it was before I added anything to it. The Dell I've just sold had a great program "Dell factory image reset" which completely cleared all my personal data etc, formatted the HD and put the computer back to as it was when I first received it.
Does Mac have a similar program please???



justperry
Apr 8, 2013, 02:16 AM
Turn on FileVault2, then create a new Admin User Account, login into that Account and delete the User you used.
That's it, don't forget to give the Password for the new User Account to the new owner.

Mrbobb
Apr 8, 2013, 02:59 AM
This 3-days old thread (http://forums.macrumors.com/showthread.php?t=1566682) talks about reloading original OS to machine.

justperry
Apr 8, 2013, 03:09 AM
This 3-days old thread (http://forums.macrumors.com/showthread.php?t=1566682) talks about reloading original OS to machine.

:confused: That thread says almost nothing about that, it has only two entries, both of them by the OP.

You really do NOT need to reinstall, if you delete the old User as in my former post all is gone and can NOT be recovered.

And if you that panicked you could delete Caches and the following files:

/Library/Caches - Contents
/Library/logs - Contents
/private/var/log - Contents
/private/var/folders - Contents
/System//Library/Caches - Contents

Secure erase Trash afterwards.

ColdCase
Apr 8, 2013, 07:08 AM
Although that clears out data, it doesn't reset the Mac back to factory, i.e. as a fresh unit.

What OS is currently on the machine? If its mountain lion or one with a recovery partition, I found this sequence posted here somewhere:

Boot into recovery mode (hold command R on bootup), navigate to the disk utility and erase the main partition (secure erase if you like). Then reboot. The machine will ask for the apple ID under which mountain lion is registered and it then reinstalls the OS. Takes a few minutes but when you are done the machine acts as its fresh out of the box.

If you have the OS on the disk, the process is the same, just boot from the disk.

justperry
Apr 8, 2013, 07:11 AM
Although that clears out data, it doesn't reset the Mac back to factory, i.e. as a fresh unit.

What OS is currently on the machine? If its mountain lion or one with a recovery partition, I found this sequence posted here somewhere:

Boot into recovery mode (hold command R on bootup), navigate to the disk utility and erase the main partition (secure erase if you like). Then reboot. The machine will ask for the apple ID under which mountain lion is registered and it then reinstalls the OS. Takes a few minutes but when you are done the machine acts as its fresh out of the box.

Better not secure erase it, it has an SSD inside, better way is to switch on FileVault2 and then reinstall.
But the way I explained above will do as well.

Weaselboy
Apr 8, 2013, 09:33 AM
I am shortly going to sell my Air and will need to put it back to where it was before I added anything to it. The Dell I've just sold had a great program "Dell factory image reset" which completely cleared all my personal data etc, formatted the HD and put the computer back to as it was when I first received it.
Does Mac have a similar program please???

Turn on Filevault2 to encrypt the disk. Then command-option-r boot to get to Internet Recovery. Now start Disk Utility and select the drive name at the top (not Macintosh HD) and erase. Then reinstall the OS.

This will wipe the encrypted data so nobody can get it back and place whatever OS your machine came with back on the machine.

It will take a bit as the 4.7GB OS needs to DL.

ColdCase
Apr 8, 2013, 12:41 PM
Better not secure erase it, it has an SSD inside, better way is to switch on FileVault2 and then reinstall.
But the way I explained above will do as well.


Good catch, secure erase SSD won't do much good.

Mrbobb
Apr 8, 2013, 12:52 PM
:confused: That thread says almost nothing about that, it has only two entries, both of them by the OP.

The Option-R Boot, although I have not tried this myself nor do I know if it works on all OS versions.

You really do NOT need to reinstall, if you delete the old User as in my former post all is gone and can NOT be recovered.

What about Apps? and their cookies, and user-related configurations?

stchman
Apr 8, 2013, 01:05 PM
I am shortly going to sell my Air and will need to put it back to where it was before I added anything to it. The Dell I've just sold had a great program "Dell factory image reset" which completely cleared all my personal data etc, formatted the HD and put the computer back to as it was when I first received it.
Does Mac have a similar program please???

If you just want to re-image the machine do the following:

Hold down the Option key while booting.

Select the recovery option.

During the process select Disk Utility and erase the SSD.

Mountain Lin will be downloaded.

Select the blank partition as the target (the installer will format for you).

~20 minutes later fresh OS.

Mrbobb
Apr 8, 2013, 01:41 PM
~20 minutes later fresh OS.

Assuming u got a fast broadband.

My 3 mbit DSL took 2 hours!

stchman
Apr 8, 2013, 02:22 PM
Assuming u got a fast broadband.

My 3 mbit DSL took 2 hours!

That's AFTER the download of ML.

ColdCase
Apr 8, 2013, 02:57 PM
During the process select Disk Utility and erase the SSD.

A persistent and motivated adversary may be able to recover much of your data. If you are paranoid, as suggested, use file vault to encrypt the drive prior to the recovery and reload steps. Even then there could be blocks left with untouched and recoverable data, so if you really want to be sure no one can extract any of your data, replace the hard drive. Destroy the old one, or put it to personal use.

stchman
Apr 8, 2013, 03:40 PM
A persistent and motivated adversary may be able to recover much of your data. If you are paranoid, as suggested, use file vault to encrypt the drive prior to the recovery and reload steps. Even then there could be blocks left with untouched and recoverable data, so if you really want to be sure no one can extract any of your data, replace the hard drive. Destroy the old one, or put it to personal use.

IIRC, Disk Utility has an erase free space option for the more paranoid out there.

ColdCase
Apr 8, 2013, 06:07 PM
IIRC, Disk Utility has an erase free space option for the more paranoid out there.

Depends on the SSD controller, but most perform wear leveling that ends up effectively moving stored data from one block to another without spending time erasing the old blocks. These old blocks are not currently visible to the OS. Someone extremely clever and with motive could read out the old data and could get lucky and find something useful there... highly unlikely.

Typical rotational drives do not have hidden memory blocks to worry about.

Encrypting the data stored on the drive from day one makes left over data look like random bits. In that case it doesn't matter what is left over until the password is cracked.

So depending on your level of paranoia.. erasing free space may not be enough :)

Weaselboy
Apr 8, 2013, 07:34 PM
IIRC, Disk Utility has an erase free space option for the more paranoid out there.

That is blocked (greyed out) in Disk Util for SSDs.

----------

A persistent and motivated adversary may be able to recover much of your data. If you are paranoid, as suggested, use file vault to encrypt the drive prior to the recovery and reload steps. Even then there could be blocks left with untouched and recoverable data, so if you really want to be sure no one can extract any of your data, replace the hard drive. Destroy the old one, or put it to personal use.

Not true. If you enable Filevault2 the entire disk is encrypted as a core storage volume. Then if you erase that volume as part of the reinstall of the OS, nobody is getting that data back. Even if one used third party tools to bring back the data, it would still be encrypted.