Mac remembers passwords after erasing

Discussion in 'macOS' started by macbookowner, Aug 9, 2015.

  1. macbookowner, Aug 9, 2015
    Last edited: Aug 9, 2015

    macbookowner macrumors newbie

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    Aug 9, 2015
    #1
    Hello!
    Do You have any idea how it's possible that Mac still remembers passwords to WiFi during reinstallation - after I successfully erased Mac OS Extended (Journaled)? It's really interesting, I thought that erasing disk with Disk Utility means that ALL data will be lost.
     
  2. SG- macrumors regular

    SG-

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    Jun 8, 2015
  3. macbookowner thread starter macrumors newbie

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    Aug 9, 2015
    #3
    I have Keychain turned off. I'm talking about 7. step of this instruction: https://support.apple.com/en-us/HT201376
    Installer automatically connect to my WiFi that I used before erasing computer (secure with password which should be forgotten!)
     
  4. Significant1 macrumors 6502

    Joined:
    Dec 20, 2014
    #4
    The system is running from the recovery partition at the time of step 7 and not the partition you erased. So nothing strange in that. It remember from last time you where connected to WiFi in recovery. Most likely when you last installed OSX, since that is where WiFi would be needed.
     
  5. macbookowner thread starter macrumors newbie

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    Aug 9, 2015
    #5
    Thanks! It's possible. Does it mean that after I erased partion, OSX still remember some personal information (ex. WiFi passwords) on on the recovery partition?
     
  6. Significant1 macrumors 6502

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    Dec 20, 2014
    #6
    I would not call it personal data. More like configuration used during installation. E.g. interface language, keyboard-layout, network configuration etc.

    WiFi password can of course be considered a bit personal.
     
  7. macbookowner thread starter macrumors newbie

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    Aug 9, 2015
    #7
    Thanks. Are there any possibilities to erase Mac completely?
     
  8. Significant1 macrumors 6502

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    Dec 20, 2014
    #8
  9. Weaselboy Moderator

    Weaselboy

    Staff Member

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    Jan 23, 2005
    Location:
    California
    #9
    https://support.apple.com/en-us/HT204063

    The Internet recovery wifi password is stored in NVRAM (firmware) and no amount of erasing the disk or erasing the recovery partition will get rid of it. After you erase the disk and do the OS reinstall, do a NVRAM reset as described at the above link and the saved wifi password will be erased from firmware.
     
  10. macbookowner thread starter macrumors newbie

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    Aug 9, 2015

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