Does factory resetting a laptop safely remove personal data

rigmaroll

As above. I'm thinking of selling my laptop and would like to remove all personal data from it before sale.

Can it be factory reset like a mobile phone

turbot

No. Even if reformatted, potentially sensitive personal data can be restored. If you want to be sure, you have to run something like killdisk to properly wipe the disk but then you may have an issue restoring the system from factory software, depending on setup and how skilled you are.

rigmaroll

Thanks, I presume the only way is to remove the hard drive but then it would be pointless selling it.

Is that correct

worded

Not perfect but consider this
Factory image it
Get a large image in a folder like a zip file of some landscape photos.
Anyhthing
Double it within the folder
Double it again
Repeat until you fill the available space on the drive
Delete the folder
You have over written your data

It's not a perfect 100% Sollution but would be better than just a factory reinstall

This isn't a prof erase of your data bit it's up to you to decide how critical your own data is

rigmaroll

I'm just concerned that bank details, passwords etc could be accessed by whoever bought the Laptop.

scamalert

just do a full format of the drive,instead of quick format,thus in that way all disk is wiped once done put new OS in and its hardly a chance anyone will recover any data,since full format goes over each sector where quick goes over the empty space to create partition,thus if enough empty space or hitting wrong sectors it might leave some data,full format goes all over drive,and if dont want to to use new OS use recovery drive to install fresh on top.

rigmaroll

Do u mean I need to purchase a new OS and install it after reformatting the drive

worded

You want to avoid a full format if you want to do a factory recovery.

If you want to avoid buying a new op sys

Google how do i deltete my data without deleting my
Recovery partition

If you have recovery Dvds - you can delete all the data on the disk using dban or the likes

Note - recovery dvds don't always work as intended. Recovery partitions usually do

Capt'n Midnight

at the very least factory restore , then turn off swapfile and hiberfile and use sdelete to wipe the free space

https://technet.microsoft.com/en-us/sysinternals/sdelete.aspx

If the laptop has windows 10 then download the media so you can do a clean install, but note your windows serial no first in case you need it - you can dban then

PJtharsaile

If the laptop has a recovery partition you should be able to copy it (and should have done so already in order to be able to recover from a drive failure). You just need to be able to initiate a recovery from this partition to revert the machine to a factory fresh installation. On Lenovo Thinkpads it's usually just a question of pressing the blue button during boot up. You may need to boot using a USB drive or a CD or DVD for other machines.

However, before doing a recovery you need to do more than just reformat or deleting the contents of other partitions. To make files unrecoverable you need to overwrite them, and merely overwriting them once may not be sufficient (depending on the contents). For a truly secure disk wipe you need to overwrite multiple times and using patterns designed to prevent recovery. There are specialized tools available such as Eraser (free) and Blancco Desktop (commercial). These are more secure than simply copying large files and then deleting.

Eraser can be downloaded here: https://eraser.heidi.ie/

jenny smith

rigmaroll wrote: »

Thanks, I presume the only way is to remove the hard drive but then it would be pointless selling it.

Is that correct

Couldn't the buyer buy a new hard disk. If concerned about privacy I would not sell the disk.You do not know where it ends up or if they can recover it. Over written several times is unlikely but maybe not impossible

scamalert

jenny smith wrote: »

Couldn't the buyer buy a new hard disk. If concerned about privacy I would not sell the disk.You do not know where it ends up or if they can recover it. Over written several times is unlikely but maybe not impossible

well prob nobody would buy laptop without hdd in it :cool:
if concerned just do full format including backup partition few times and should be fine put windows 10 on trial and let it go,if buyer is any good with pc's they will get key for 20e or so to activate it,since in many cases people would put new OS themselves or clean install just to make sure performance wise its not carrying any leftover files.Since data recovery is expensive in general,and doubt theres many people interested in doing it.if still paranoid just buy new hdd they go for little to nothing nowadays 50e for couple hundred gigs.

PJtharsaile

jenny smith wrote: »

Over written several times is unlikely but maybe not impossible

The NSA cannot recover data from a drive that has been properly overwritten using tools like Eraser (free; already mentioned) or Blancco (commercial). One overwrite will suffice in most cases but theoretically data could be recovered using specialist tools reading residual magnetism. Repeated overwrites using specialized patterns can make that impossible even for the NSA (more secure than just random overwriting by file copying).

Hard drives are cheap and if the computer is any good there's a chance it's worth replacing it with a newer one, perhaps an SSD.

jenny smith

PJtharsaile wrote: »

The NSA cannot recover data from a drive that has been properly overwritten using tools like Eraser (free; already mentioned) or Blancco (commercial). One overwrite will suffice in most cases but theoretically data could be recovered using specialist tools reading residual magnetism. Repeated overwrites using specialized patterns can make that impossible even for the NSA (more secure than just random overwriting by file copying).

Hard drives are cheap and if the computer is any good there's a chance it's worth replacing it with a newer one, perhaps an SSD.

How do you know what the NSA can do or will be able to do in the future. They would tell you? I would not ever sell a hard disk anyway. If someone is too mean to buy a disk they do not deserve a cheap laptop

scamalert

jenny smith wrote: »

How do you know what the NSA can do or will be able to do in the future. They would tell you? I would not ever sell a hard disk anyway. If someone is too mean to buy a disk they do not deserve a cheap laptop

first its not conspiracy forum here,second reason why op would have hard time selling laptop since people buying it would want to verify at least that specs are correct,and theres no faults with it.

PJtharsaile

jenny smith wrote: »

How do you know what the NSA can do or will be able to do in the future. They would tell you? I would not ever sell a hard disk anyway. If someone is too mean to buy a disk they do not deserve a cheap laptop

As you asked:

The US govt and US military publish standards for secure disk erasure intended to ensure that data is not recoverable from hard drives. The algorithms are known and are implemented in software such as Blancco, which I mentioned, so yes, in fact, by implication the NSA has made public what is required to ensure that foreign adversaries of the US cannot recover data. I made no predictions about future NSA capabilities nor do I intend engaging in any such discussion; just pointing out that paranoia about data recovery from an old drive is misplaced if basic and easily implemented measures are followed. If you have data that would warrant extreme additional precautions the standard advice is to destroy the drive with an angle grinder.

newtech

I'm selling the pc this weekend and need to clean it first.

I have copied Windows 10 to a Dvd in order to do a clean install later.

First I want to use Sdelete to overwrite files and then erase the hard drive using DBan.

I've downloaded Sdelete to My Documents folder and tried to use the command prompt to erase the drive using this command Sdelete z- C: but I keep getting an Sdelete is not recognised as an internal or external command, operable program or batch file.

Does anyone know how to use the command prompt with Sdelete. What are the exact file paths I need to use.

Thank you

Capt'n Midnight

did you unzip sdelete ?

did you CD into the documents folder ?


dban will take hours , more a reflection of how big drives are

newtech

Capt'n Midnight wrote: »

did you unzip sdelete ?

did you CD into the documents folder ?


dban will take hours , more a reflection of how big drives are

Yes and when I did there were three files. One was a eula text file. The other two were exe files, one is named sdelete and the other is named sdelete64. My system is 64bit so I presume I use this one.

I don't know what you mean by did you CD into the documents folder.

newtech

newtech wrote: »

Yes and when I did there were three files. One was a eula text file. The other two were exe files, one is named sdelete and the other is named sdelete64. My system is 64bit so I presume I use this one.

I don't know what you mean by did you CD into the documents folder.

Can anyone else help with this. Does sdelete have to be run before dban or can I run dban and then use sdelete after.

Thanks

Capt'n Midnight

dban wipes everything, so you'd have to do a full install later on



sdelete only wipes what you tell it , it won't wipe the swapfile, or internet caches,

to use ANY program from the command line it has to be in a folder listed in PATH or you have to type in the folder name or you have to CD to the folder.

newtech

Capt'n Midnight wrote: »

dban wipes everything, so you'd have to do a full install later on

sdelete only wipes what you tell it , it won't wipe the swapfile, or internet caches,

to use ANY program from the command line it has to be in a folder listed in PATH or you have to type in the folder name or you have to CD to the folder.

Thanks for your help.

I am going to do a full install later. Do you mean that if I'm going to use Dban it's not necessary to use sdelete. Will dban delete the swapfile and hiberfile also.

If I do still need to use sdelete can you let me know how to write the command correctly when the sdelete exe file is in the downloads folder.

I'm not a techie and tried following instructions online but there are not very clear. I can't post the link to the instructions as I'm a new user. I'll type in the url later with spaces.

Here is where I found the instructions
http / www.guidingtech.com/2834/ sdelete-permanently

newtech

newtech wrote: »

Thanks for your help.

I am going to do a full install later. Do you mean that if I'm going to use Dban it's not necessary to use sdelete. Will dban delete the swapfile and hiberfile also.

If I do still need to use sdelete can you let me know how to write the command correctly when the sdelete exe file is in the downloads folder.

I'm not a techie and tried following instructions online but there are not very clear. I can't post the link to the instructions as I'm a new user. I'll type in the url later with spaces.

Here is where I found the instructions
http / www.guidingtech.com/2834/ sdelete-permanently

Can anyone else confirm whether it's necessary or unnecessary to use sdelete if your using dban also to wipe the HD.

I need to get this done today so advice is appreciated.

soirish

Why not try what Hillary is using https://www.bleachbit.org/

newtech

soirish wrote: »

Why not try what Hillary is using https://www.bleachbit.org/

I think I'd be better following Donald and ask the Russians how they would do it.

I want to actually use the method that's been mainly recommended in this thread. I'm surprised there isn't a consensus on the best method and that it's not stickied outlining the steps to take considering boards members sell laptops on adverts.ie

beauf

If you are not technical remove the hard drive. You can reuse it as external backup.
Sell the laptop without a hard drive. It won't make that much difference.
That's the easy option.

Anyone buying a laptop should replace the HD with a SSD unless they really need a lot of storage space.

Formatting doesn't wipe the drive. Formatting even a full format might not actually do a full format depending on the OS you are using. So forget formatting. You need overwrite it. Erase it.

Hard to know with factory reset, some just format, some erase. Also some laptops are set up with recovery partitions, or maybe backups are stored somewhere else. So you need to know what you are doing to wipe these properly. Also its hard to overwrite SSD they might not be erased even with OEM tools.

To be sure to sure, remove the drive and physically destroy it. If you are not technical.

The only gotcha is you might need to get the OS (Windows )image off the drive before destroying it. You'll need to have some technical skills to do that.

beauf

newtech wrote: »

..I'm surprised there isn't a consensus on the best method and that it's not stickied outlining the steps to take considering boards members sell laptops on adverts.ie

A lot of the advice while well meaning is wrong.

Wiping a hard drive is not hard. But you need to know what you are doing. There isn't one best way. you can do a few different ways.

You should considering encrypting a laptop once you buy it. Especially if it as a SSD. Then you won't be worried about someone else getting your data if it gets stolen from your home or you leave it in a taxi etc.