How to really erase old files in my laptop?

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  • #26
DaveC426913
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It seems to me that there's a penny-wise pound-foolish thing happening here. Master-level data wiping requirements but no consideration for other locations of user-specific content.

The OP wants to keep the software app, while only erasing data. The line between software and data is more and more blurry these days.

If the OP wants a level of wiping that is essentially pro-quality, he is not going to get that by leaving software on the computer - even if he wipes data.

Examples:
  1. It can be a simple matter of the intended recipient opening up, say, Word, and looking in the Recent Files list and inadvertently seeing 'Twilight Slashfic-fap.doc' as the last doc accessed (despite that file having been erased).
  2. Some programs store data with software. An HTML page can embed an image in CSS as a string. Simply opening that HTML page would reveal the image. No data wiper will find that if it's not in a well-managed location.

Sure, setting up a new user and deleting the old one ought to clear your personal settings, but really there's no way to be sure. Some programs don't abide by the Windows standards, and don't store all user data in the user folders. Some store their data in their own application folders. You won't be able to clear those easily while still keeping the software intact.

The level of expertise required to literally recover wiped data is much higher than the level of expertise to find remnants of previous use, as suggested above.

I don't think there's any way to guarantee what the user wants. Either wipe the drive completely and start fresh, or reconcile your expectations with a small but non-zero chance of getting busted.
 
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  • #27
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Hi Guys, Thanks for all the suggestions. I am giving the computer to my granddaughter only, there's nothing illegal, secret or high value information. My wife used the computer before, there are bank account info, tax information etc.

I learn a lot on this, I understand what I did is not good enough, it's just where to draw the line. I fill 3 times with big files, but after I read the information here, I learn using big files is NOT a good idea as it leaves gaps in between. So the 4th time, I just put a lot.....I mean a lot of small pdf files into a folder to make up 1.2G size. Then I copy that folder over and over until the warning message. I did disk clean up to free space, then fill more.

When it get to very full, I started copy small files a few at a time, clean disk until there's no room to even put a 20KB file. Yes, it is much harder to get full, but I think I write over a lot more complete this time.

I am not trying to be stubborn, like I said before, after I read news like Tik Tok and other software can spy on people, I just rather do a lesser way than to try to run external eraser if I can help it.

So I erase and filled 4 times already. I hope it does count for something. I was hoping I can get instruction within Windows to erase, but I guess not.

Thanks
 
  • #28
Vanadium 50
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A lot of ideas are getting twisted together here.

First, there are levels of security:
  • Keeping your little sister out
  • Keeping a determined criminal out
  • Keeping a major world government out
In the middle tier, a drive can be recovered for around $1000.

The idea of residual magnetization goes like this. Data is digital, but the read/write mechanism is fundamentally analog. Suppose what's recorded is 10101010... Then it's erased to 00000... but what might actually still be on the drive is 0.1-0-0.1-0-0.1 etc. Now let's write 110110110. What might actually be on the drive is 1.1 - 1.0 - 0.1 - 1.0 - 1.1 - etc. In principle one can recover the original 10101 pattern. In practice, this is more complicated, and it's not clear it can be done by anything less than a major world government.

Disk erase software writes random patterns multiple times. It's unclear how many passes it takes to keep major world governments out: DOD used to say three. Well, if the same software protects you from likely threats with one pass and unlikely ones with three, why not use three when you can?

Things are somewhat different with SSDs, but that's not the subject at hand.

Now, if you don't reinstall Windows, Windows may well keep its own copies of various pieces of data. It won't even keep your little sister out. So your answer is simple - use a utility to overwrite the disk, ideally three times, and then reinstall Windows.
 
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  • #29
rbelli1
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So I erase and filled 4 times already. I hope it does count for something. I was hoping I can get instruction within Windows to erase, but I guess not.

A double NSA KGB super duper wipe of the free space does nothing for the file slack. Or anything you missed deleting. Or backups or temporary files made by Windows or your other software. Or leftovers in hibernation and swap files. Or any of the spare sectors on the SSD. Or something else I or the other posters here forgot.

Your sorta almost free space wipe is even less effective.

Nuke it from orbit and reinstall like Vanadium 50 and others have suggested.

BoB
 
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A double NSA KGB super duper wipe of the free space does nothing for the file slack. Or anything you missed deleting. Or backups or temporary files made by Windows or your other software. Or leftovers in hibernation and swap files. Or any of the spare sectors on the SSD. Or something else I or the other posters here forgot.

Your sorta almost free space wipe is even less effective.

Nuke it from orbit and reinstall like Vanadium 50 and others have suggested.

BoB
The DBAN product page to which you linked says "It cannot detect or erase SSDs"; however, it has a link for a trial for a drive eraser product that it says works on SSDs ##-## I think that @yungman would do better to use the manufacturer's (HP's) readily available method.
 
  • #31
rbelli1
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"It cannot detect or erase SSDs"

I think that @yungman would do better to use the manufacturer's (HP's) readily available method.

I've never needed to erase an SSD so was unaware of that limitation. Also I wanted to to say "Nuke it from orbit".

"HP Disk Sanitizer" it from orbit just doesn't have the same ring to it.

You are right that the manufacturer specific product is the best option.

BoB

Edit: Crap HP Disk Sanitizer is only for spinning disks too. Their Secure Erase program does SSD's.
 
  • #32
Laroxe
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I just use CCleaner free from Piriform, its easy and its never caused me any problems. You can go to the - Options then settings then select secure deletions, you can then select how many times data is overwritten, though the more times the slower the process. There are some other options you can use as well, the very complex is only worthwhile if your trying to prevent the NSA getting any data. I find it very easy to use and also use it to declutter my drives, it gets rid of masses of rubbish. The first run it will find stuff you didn't know existed so give it time to do its job.
 
  • #33
Vanadium 50
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We're still getting advice on how to erase the unused space but leaving Windows installed.

As pointed out, Windows and its applications often store copies of data on their own, often in unexpected places.

If we were talking about a physical file with two copies, it would be like taking one copy, shredding it and burning the shreds and scattering the ashes - but leaving the other copy intact, and then arguing about what the best shredder to use is.
 
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  • #34
DaveC426913
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As pointed out, Windows and its applications often store copies of data on their own, often in unexpected places.

If we were talking about a physical file with two copies, it would be like taking one copy, shredding it and burning the shreds and scattering the ashes - but leaving the other copy intact, and then arguing about what the best shredder to use is.
This, exactly.
 
  • #35
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I just use CCleaner free from Piriform, its easy and its never caused me any problems. You can go to the - Options then settings then select secure deletions, you can then select how many times data is overwritten, though the more times the slower the process. There are some other options you can use as well, the very complex is only worthwhile if your trying to prevent the NSA getting any data. I find it very easy to use and also use it to declutter my drives, it gets rid of masses of rubbish. The first run it will find stuff you didn't know existed so give it time to do its job.
CCleaner is good for wiping free space on HDDs, but its maker recommends not using it for wiping on SSDs. To remove any remnants of deleted files on SSDs, while retaining other files, do a non-raw full-device backup, then a manufacturer-approved sanitize or erase, then a restore. For secure erasures on SSDs, it's better to not try to use HDD-specific techniques, such as single or multi-pass overwrites.
 
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If you really want to be sure... replace the hard drive in it
 
  • #37
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If you really want to be sure... replace the hard drive in it
That alone would of course not preserve any content; if it were done along with a correct backup and restore, it would be sufficient but not necessary.
 
  • #38
harborsparrow
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It turns out, Microsoft finally built in a utility for overwriting and clearing free space. And I've tried it and it seemed to work well. I learned about it from this article:

https://www.howtogeek.com/137108/how-securely-overwrite-free-space-in-windows/

The command is:

cipher /w:C:\

where C is the letter of the drive you want to securely overwrite the free space on.

Use a command prompt window with Administrative privileges.

Don't run anything else while it's going on. Expect it to take hours, possibly run it overnight.
 
  • #39
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It turns out, Microsoft finally built in a utility for overwriting and clearing free space. And I've tried it and it seemed to work well. I learned about it from this article:

https://www.howtogeek.com/137108/how-securely-overwrite-free-space-in-windows/

The command is:

cipher /w:C:\

where C is the letter of the drive you want to securely overwrite the free space on.

Use a command prompt window with Administrative privileges.

Don't run anything else while it's going on. Expect it to take hours, possibly run it overnight.
It's not for SSDs.
 
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