Clearing hard drive

[Stevemr]

Hi folks
I have an old laptop that I want to give away.
It will in the past have had some work related information on it.
If I do a factory reset, does that completely clear the hard drive?
Or would there still be a way for someone to access that information?

[Scabutz]

There is an option in Windows to "remove everything". I'm snot sure how final that really is though. Years ago I worked for the police and the Head of the computer crime unit said unless you tale a magnet to it and then smash it to pieces we can still get data off it.

There are 3rd party tools that might be more robust.

If you were really worried I would sell it sans hard drive.

[M11rph]

Assuming this is an SSD then open the BIOS and see if there is a Secure Erase feature.

HDD's are so cheap it is best to simply remove it and physically destroy them.

Depending on what data you had on the existing drive and the value of the device swapping out the old drive is the best way to be absolutely certain.

[nyt]

https://www.lifewire.com/free-data-destruction-sof...

I used to work with a PC recycling charity and the financial organisations that donated their equipment were happy as long as we ran at least two deletion utilities before sending off the machines to developing countries.

[Mr Pointy]

Eraser will remove everything:

https://eraser.heidi.ie/

You'll need to re-install an OS afterwards.

[Ledaig]

Stevemr said:

If I do a factory reset, does that completely clear the hard drive?

No, the information will still be there on the hard drive - just not referenced. It's the same if you just delete something, all you're doing is removing the reference to the file within Windows and telling it that the space on the hard drive can be reused (and the obsolete information over-written) by designating it 'free space'.

Imagine you have a book with say, 10 chapters. Each chapter is referenced in a list of contents at the beginning of the book, and you can only access a chapter from that contents list.
If you want to delete chapter 8 for example, you tell the book (yes I know, but go with it ) and it 'deletes' chapter 8 by removing the reference to it in the list of contents.
But chapter 8 is still there, your just not allowed to read it anymore as you can't find it as it's no longer referenced in the contents.
What you have done though is created 'free space' in the book where a new chapter can be written, overwriting (in part or full) the old chapter 8 and associated information.
Now if someone comes along with a crowbar (recovery tool), they can prise open the book and still read chapter 8 in full.

Stevemr said:

Or would there still be a way for someone to access that information?

Yep - apply your factory reset and then pop the drive in the post to me, I'll plug it in a dock and extract everything still there - including stuff you've probably long forgotten about

Mr Pointy said:

Eraser will remove everything:

https://eraser.heidi.ie/

You'll need to re-install an OS afterwards.

Now the above is a good shout. Eraser has a function to 'erase' free space - this is what you need. If you run the factory reset and then load eraser, you can right click on the drive to access the 'erase unused space' function.
This may not get you out of forensic levels of recovery, but should be good enough for what you need...