Helping people with computers... one answer at a time.

Reinstalling Windows erases and overwrites the data on your machine. Recovering it is difficult, if not impossible.

Hi, Leo. I need your help as I'm in big trouble as I'm having a Compaq laptop and while doing recovery of my laptop to factory default through its discs, which I got from HP, my hard disk got formatted and as a result, my 250 GB of crucial information seems to be lost as while installing another Windows on the disk partition free space that shows 250 GB only. Please help me out on how to proceed further to recover my crucial data. I would be very obliged to you.

In this excerpt from Answercast #15, I look at a scenario where crucial data has been deleted during an accidental reinstallation of Windows. A backup would have saved the day.

Overwriting data

So, this one is a tough one. The short answer is: chances are highly unlikely that you will be able to recover anything from that machine.

However, what I would suggest you do immediately in a case like this is:

A) Stop using the machine: because the more you use the machine, the more any data that might still be there is going to be overwritten and unrecoverable.

B) I would then either take the hard disk to a data recovery expert or install the hard disk in an external USB enclosure connected up to a different computer that's working, and start running tools like Recuva on it.

Data recovery

Recuva will look in the unallocated space that remains on the hard disk and try to locate any files that were on the hard disk before it was formatted.

It's unlikely that this will be successful; it could recover some stuff (don't get me wrong), but I think that you'll in the long run end up being very disappointed.

Depending on how the disk was formatted, it is possible that everything was overwritten.

When you installed Windows (when Windows started those files that comprise this new version of Windows; this recovery that you did through factory defaults), all those files that were copied on to the hard disk probably overwrote the information that was there.

Now, obviously, that didn't fill up the entire hard disk, which is why there's a possibility some of your files could still be there. The files that have been overwritten (unless you're willing to spend a boatload of money on recovery) are lost and gone forever.

A full backup would save you

One of the reasons that I'm taking this question and posting it publicly is that this is a classic case of having your data in one and only one place.

You were not backed up.

Restoring to factory defaults by definition erases everything on your hard disk. So that was just a conceptual mistake that was made in this process

But you didn't even have to make a mistake! If that hard disk had died, then all of your information on it would have been lost forever as well.

  • The only solution is to back up, back up often.

Regardless of whether or how much data you can recover from this scenario, I hope that you will learn from this and that others will learn from the example.

  • If you have it in only one place; your data is not backed up.

Copy it somewhere else and I don't mean another hard disk in the same machine. I mean another place - an external hard disk, another computer, online.

I honestly don't care. Just so that it's copied; there's a copy of your important data somewhere else. If it's really that crucial as you put it, then it's worth backing up.

End of Answercast #15 Back to - Audio Segment

Article C5311 - May 7, 2012 « »

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Leo Leo A. Notenboom has been playing with computers since he was required to take a programming class in 1976. An 18 year career as a programmer at Microsoft soon followed. After "retiring" in 2001, Leo started Ask Leo! in 2003 as a place for answers to common computer and technical questions. More about Leo.

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6 Comments
Charles
May 9, 2012 3:02 PM

Such software restoring disc utilities always have you acknowledge, sometimes twice, often in capital letters, that you are going to LOSE ALL DATA if you let them proceed.

I guess this brings up another common issue with users not reading what dialog boxes say.

Gwyn
May 9, 2012 3:36 PM

"When you installed Windows (when Windows started those files that comprise this new version of Windows; this recovery that you did through factory defaults#, all those files that were copied on to the hard disk probably overwrote the information that was there.

Now, obviously, that didn't fill up the entire hard disk, which is why there's a possibility some of your files could still be there. The files that have been overwritten #unless you're willing to spend a boatload of money on recovery) are lost and gone forever."

Are you saying here that if you restore a pc to its factory settings, not everything that was not on the machine when it left the factory will be wiped?

Mark J
May 10, 2012 1:42 AM

@Gwyn
Restoring to factory settings would just overwrite the amount of data that it would be writing to the drive.
According to Murphy's law, that's enough to destroy the files you're looking for, but not enough to keep you out of trouble if a hacker were to try to access that data. ;=)

John Servis
May 11, 2012 1:51 PM

Hello Leo, I repair Laptops/Desktops as a small home business and it NEVER ceases to amaze me the response I receive from more than 1/2 of my clients when told I can't help them when it comes to recovering "important" files from a H.D. that has failed and was never backed up. Not to mention the look on their faces. The reply above referring to how many prompts one must go through in order to reinstall/reformat a drive is correct as well. I don't think people give any thought to pushing the enter button without regard of the outcome, or they don't read before acting? I don't understand, but I do know this whole scenario could have been prevented.

Owen Marks
June 1, 2012 2:20 PM

Leo, I'm an IT consultant, and a friend of mine did a factory-restore, not realizing that the warning "this will erase everything" meant "this will erase everything". I used some easily available inexpensive recovery software (there are many choices). It took about a week and required multiple passes, but I eventually got about 80% of the data back. Very messy; I highly recommend reliable backups instead!

Chandresh
February 5, 2013 3:02 AM

@ Owen Marks
Hello,

My laptop was recently restored to Factory Settings and I lost all my photos and Videos of my kid on that Laptop. I lost almost 7 years of images and videos.

Can u tell me which software will help me getting most of the data back. ?

Thank You and Regards

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