Erased HD-Don't Erase Option-Anyway to Recover?

Discussion in 'Mac Pro' started by musicguy7, Oct 12, 2011.

  1. musicguy7 macrumors member

    Jun 21, 2011
    I was formatting a new HD I bought in a usb enclosure, and picked an internal HD to erase instead. Yes, I'm aware this was highly idiotic. I chose the don't erase option, and it mentions "disk recovery applications" may be able to recover data, so I was wondering what these were? Also, after the erase, I transferred about 800 gigs of media to it, there was less than 100 gigs on it originally that I want to erase, if that info means anything...
  2. ActionableMango macrumors G3


    Sep 21, 2010
    That right there pretty much ruined your chances of recovery. You can try DiskWarrior, but I doubt you'll get much out of it.
  3. minifridge1138 macrumors 6502a

    Jun 26, 2010
    I'd say that your chances are slim to none of getting the data back after writing 800GB of data to the drive.
    You might be able to recover some of the data, but that would take luck.

    Any chance you have a back up of the drive (time machine, SuperDuper, Carbon Copy)?
  4. musicguy7 thread starter macrumors member

    Jun 21, 2011
    Well I was thinking maybe since originally there was less than 100 gigs, that the new 800 wouldn't be overwriting the same "place" as the 100 gigs? Did I guess wrong how HDs work here?
  5. Loa macrumors 68000


    May 5, 2003

    You can try those recovery apps (you can search for some, using the word recovery, on, but the fact that you wrote 800GB of data after erasing means that those 800GB have been written "over" the previously deleted 100GB.

    Sadly, I wouldn't hope for anything, except that dreadful lesson about having back-ups.

  6. minifridge1138 macrumors 6502a

    Jun 26, 2010
    The problem is that it's impossible to know where the 800GB was written to.

    You may be lucky, and the 800G was written to the part of the drive that wasn't used by the 100G that your old data was in. But that's Extremely unlikely.

    Imagine a friend says "i'm thinking of a number between 1 and 10. Guess the number. And I'll give you 8 chances." Assuming it was a 1TB drive, that's exactly what you did. You most probably overwrote the old data.

    Typically, the drive is going to try and use the first block of data it can find that will hold your file. Since you just erased all of the data, it could have written anywhere. I know you selected 'don't erase the data' but that isn't what it sounds like.

    Think of a hard drive kind of like a book. The first page in the book is the table of content. It tells you what chapter is on what page. The actually story is on the pages. Any page not listed in the table of content is considered an empty page and you can write on it.

    When you format a drive and select "don't erase" you just delete the table of content. The story is still written on the old pages. But since the TOC is blank, the next person that wants to write will see that all of the pages are available and start writing over what was written on the page. This is fast, because you're only delete the table of contents. And some software can recover the hard drive by re-reading the pages and recreating the TOC.

    When you format a drive and select "erase content" you delete the table of content AND you write over everything written on all of the pages. It takes a lot longer.

    In your case, after you formatted the drive the 100G of data was still on the disk. So you might have been able to recover the data. But when you wrote the 800GB onto the drive, it most likely used part of the drive that had been used before.
  7. musicguy7 thread starter macrumors member

    Jun 21, 2011
    Alright, and I am now attempting to using Data Rescue, and this thing takes 3 mins per GB for a deep scan of the 1 TB drive! prolly not worth it at this point...I had some nice projects I recently worked on, but no masterpiece symphonies I guess...
  8. JavaTheHut macrumors 6502


    Aug 15, 2010
    Ahh! it doesn't matter you had backup right... nudge nudge wink wink

    We are all fallible especially I
  9. nanofrog macrumors G4

    May 6, 2008
    Had you performed a recovery directly after the format, most, if not all of the data should have been recovered.

    Unfortunately, since you wrote data first, and it's more than the capacity of the files you wanted to recover, there's not going to much, if any, complete files of the original data remaining (file fragments are more likely for any original data that still remains on the platters; think random access files written to sectors that previously contained large contiguous files).

    Hopefully, you had a backup. Given a later post however, I've the impression you didn't. :( A rather hard way to learn to keep backups, but it's a lesson not easily forgotten. ;)

    Unfortunately, the disk likely started back at the beginning once the Partition/Address Tables were cleared out (started back at the first block that data is written to), thus writing over most, if not all of the original files.

    Even if the disk was fragmented, it's doubtful much/any of the original content was written beyond the 800GB mark. :(
  10. bluesteel macrumors 6502

    Apr 5, 2007
    i've done something similar in the past. i used R-Studio file and data recovery software by a company called R-Tools. i was able to recover about 90% of the data erased from my hard drive. in addition to the data i had lost at the time, R-Studio even recovered data i had erased a few years back. its not easy sorting through it all, though. its been a year and i still haven't sorted through all the recovered files, but i did immediately find many files that i needed.

    i will admit that i was real skeptical at first, so i decided to use the trial. when i saw that it worked i bought the full version. i don't think any of this file and data recovery software out there is perfect, but R-Studio was pretty cool in how it recovered my data of an erased hard drive. it might not work for you, but it worked for me.

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