Best way of wiping all data from our laptops

Giraffe76

Active Member
Hi all,

We have a couple of laptops that we are looking to sell but want to wipe them of all data before doing so.
Can someone tell me the best& possibly a free way of doing this task please

Kind regards Mark
 

Bigfingers

Distinguished Member
Hi all,

We have a couple of laptops that we are looking to sell but want to wipe them of all data before doing so.
Can someone tell me the best& possibly a free way of doing this task please

Kind regards Mark
Eraser or file shredder are two better known free programs.
 

brunation

Well-known Member
We have a couple of laptops that we are looking to sell but want to wipe them of all data before doing so.
Can someone tell me the best& possibly a free way of doing this task please
Check the laptops for a factory reset option to restore the system as new.
 

John7

Well-known Member
Factory reset will not securely erase data from hard drives. Someone intent on retrieving sensitive personal data from the hard drive would be able to with the right software.

AFAIK the best way to erase the disk securely would require you to run a secure disk erasing utility software on it. Once done, you would need to reinstall the operating system. I can't recommend any particular software as I have no experience - I normally remove hard drives and physically destroy them.
 

EndlessWaves

Distinguished Member
For normal hard drives you can overwrite the data, for SSDs you need to trigger their own secure erase function as they have reserved capacity you can't normally overwrite.

A factory reset may include this functionality. Windows 10's Reset option includes this but if your machine pre-dates or doesn't use this then you'd need to look elsewhere.

What types of drives and which operating system are the machines using? There isn't a single option that works for all laptops over the past 10-15 years.
 

brunation

Well-known Member
Once done, you would need to reinstall the operating system.
So before you do anything ..... check if a factory reset exists. Know what you're wiping.
 
Last edited:

Monster900

Active Member
Hi all,

We have a couple of laptops that we are looking to sell but want to wipe them of all data before doing so.
Can someone tell me the best& possibly a free way of doing this task please

Kind regards Mark
This is not as easy a question to answer as it first appears.

A lot depends on how risk tolerant or averse you are. If you are selling the laptops to trusted family or friends you may want to do things differently from if you're selling on a well known auction site or car boot sale. It also depends on whether you want to sell the laptop with or without the OS or other installed software.

As I said, not quite such an easy question to answer.
 

Bigfingers

Distinguished Member
Just take the hard drive out, plug it into another pc, run Eraser or file shredder on a high grade sanitiser, eg: DOD 5220-22-M or Gutmann and clean the whole disk. You can then reinstall fresh with the OEM license key, assuming you have one.
Unless your worried you are an NSA target, that will be sufficient for selling on. It really is that straight forward.
 

Monster900

Active Member
Just take the hard drive out, plug it into another pc, run Eraser or file shredder on a high grade sanitiser, eg: DOD 5220-22-M or Gutmann and clean the whole disk. You can then reinstall fresh with the OEM license key, assuming you have one.
Unless your worried you are an NSA target, that will be sufficient for selling on. It really is that straight forward.
If you're going to erase the whole disk you don't even need to remove the drive if you use something like DBAN.
 

noiseboy72

Distinguished Member
For the sake of £35, I would simply put in a new hard drive and destroy the current one. Simply break the platter and data recovery is impossible.
 

EndlessWaves

Distinguished Member
Just take the hard drive out, plug it into another pc, run Eraser or file shredder on a high grade sanitiser, eg: DOD 5220-22-M or Gutmann and clean the whole disk. You can then reinstall fresh with the OEM license key, assuming you have one.
Unless your worried you are an NSA target, that will be sufficient for selling on. It really is that straight forward.
That'll only work on storage such as traditional hard drives where all of the permanent storage is exposed to the OS. Anything with spare capacity such as SSDs and Hybrid drives can't be fully wiped using that method.
 

Bigfingers

Distinguished Member
That'll only work on storage such as traditional hard drives where all of the permanent storage is exposed to the OS. Anything with spare capacity such as SSDs and Hybrid drives can't be fully wiped using that method.
The OP didn't say he had, so I can only go on the info he gave.
 

Monster900

Active Member
That'll only work on storage such as traditional hard drives where all of the permanent storage is exposed to the OS. Anything with spare capacity such as SSDs and Hybrid drives can't be fully wiped using that method.
Although I knew that you should use the SSD manufacturers secure delete for SSDs, exactly what sort of data is stored in those areas that are not accessible to the OS?

Just interested to know.
 

EndlessWaves

Distinguished Member
SSDs have more capacity than they present to the OS, it's known as over-provisioning and allows them to spread writes evenly across the disk to increase it's lifespan.

An SSD may present itself as a 100GB drive but it'll have 128GB of actual storage capacity. The locations on the 100GB disk the OS sees bear no relation to the actual physical locations of data, that's determined by the controller of the SSD.

So if you were to write 200GB to it then it'd result in some storage locations being overwritten three or four times by others only marked as empty but not being overwritten at all.
 

Monster900

Active Member
SSDs have more capacity than they present to the OS, it's known as over-provisioning and allows them to spread writes evenly across the disk to increase it's lifespan.

An SSD may present itself as a 100GB drive but it'll have 128GB of actual storage capacity. The locations on the 100GB disk the OS sees bear no relation to the actual physical locations of data, that's determined by the controller of the SSD.

So if you were to write 200GB to it then it'd result in some storage locations being overwritten three or four times by others only marked as empty but not being overwritten at all.
Thanks for the explanation.

I was aware of the concept of over-provisioning and aware that it is sometimes seen as 'unallocated' space in normal disk management software (it is on my Samsung 840 anyway). I guess on some other SSD the over-provisioning is pre-allocated and really is only visible to the controller. What I hadn't realised is that the SSD routinely writes to the over-provision space as part of the over-provisioning function. I had thought that if part of the disk was reported as 'bad' to the controller that it would swap some of the unallocated over-provisioning space to be part of the formatted disk volume and the overprovisioning space would slowly fill up with failed locations which are no longer accessible to anything, similar to my understanding of how HDD work. Clearly from your explanation that is not how it works and the over-provisioning area is used all the time.

Thanks again for improving my understanding.
 

EndlessWaves

Distinguished Member
it is sometimes seen as 'unallocated' space in normal disk management software (it is on my Samsung 840 anyway).
It's not normally shown in disk management, although it's possible to increase it manually by leaving unallocated space which may have been what was done on your PC (or it's something to do with the workaround for the 840 Evo issues).
 

Monster900

Active Member
It's not normally shown in disk management, although it's possible to increase it manually by leaving unallocated space which may have been what was done on your PC (or it's something to do with the workaround for the 840 Evo issues).
Apologies it is actually have a Samsung 850 EVO.

On this SSD over-provisioning is manually set through Samsung Magician software. I have set mine to the recommended amount, 10%, which is 23.29 GB and that is the exact same amount that appears as 'unallocated' in Windows 10 Disk Manager.

Other SSD Crucial, Kingston etc., that I have put in other machines, I just clone the old disk to the new SSD connect it up and away to go. So it looks like Samsung are the outliers here.
 
I generally just boot Parted Magic and use secure erase. Good enough for personal use and most business operations.

If there is a specific concern about a SSD then a trick could be to full disk encrypt it, and then erase the disk. That will make certain all files are deleted opposed for forgotten.

But anyway, boot from parted magic and run secure erase. Job done.
 

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