'erase free space' not secure - it doesn't seem to work?

Just wanted to point out that the erase free space option in Mountain Lion does not seem to work, at all.
A week ago I ran erase free space on my primary data drive then later, out of curiosity, I ran an inexpensive third party recovery program on the disk just to see what happened. Interestingly enough the recovery software was able to find and restore files that I had deleted over a year ago.
This has me thinking, so today I tried it again, only with a 7 pass erase this time. Nope, same thing. After a 7 pass erase (erase free space) this low end, less than $35 recovery software turns up tons of files, everything from stuff I just deleted a few days ago to stuff from over a year ago.
If I'm doing something wrong I would love for someone to point it out to me. Not that I'm toting state secrets or anything on my mac, but still - my privacy is important to me and I assume it is to others.
I'd encourage folks to try this out for themselves.
My set up is a 2011 macbook pro with an SSD as the boot drive, I've got a second harddrive installed in the optical bay and this is where my home folder lives. The secondary drive is the drive where I'm running erase free space.
The only thing that I can think of is that, even though the button is not greyed out, maybe I need to be booted to recovery in order to succesfully run erase free space on system drives?
Any input would be greatly appreciated, otherwise this seems like a pretty ugly security lapse on the part of Apple. Imagine if you're selling your machine and secure erasing before turnign it over to its new owner - and the new owner can run a $35 dollar recovery program and access everything on your machine.
Not good.

Thanks for your response, William.
I think that the issue may have to do with being booted to the system while trying to erase free space. I ran a 7 pass erase free space on a 1TB external Lacie drive this afternoon, the operation took a bit over 6 hours to complete and recovery sofatware is turning up nothing.
This is in contrast to the main drive, which my original post referenced, which is a 500gb 7200 rpm internal drive. A 7 pass secure erase took less than 5 minutes to complete - so, even though the drive is 1/2 the size, there's obviously something not right with the 7 minutes time to complete.
Tomorrow I'm going to try either booting to another account (which doesn't utilize this partcular disk) or booting to recovery and seeing what happens.
I have a feeling that this will solve the problem - I'll post back tomorrow evening.

Similar Messages

Disk Utility Error - Secure Erase Free Space failure

I have encountered a problem which I can't solve: I've used the secure erase feature to wipe unused parts of the disk before without problem. Now I get the following error message each time I try to use Disk Utility to do so:
"Secure Erase Free Space failed
Secure Erase Free Space failed with the error:
Could not create temporary file"
I tried it with the hard disk on the computer, my external backup disk, and a USB thumb drive. Same error message in each case.
If anyone knows the solution I would appreciate the help. I've scoured these fora and the internet to no avail.
Thanks.

Tried booting from another hard drive and running Disk Utility Repair Disk? follow up with Disk Warrior after that.
I would just do a full volume clone, reinitialize, and restore.

Secure erase free space on SSHD

I have a 500Gb Toshiba SSHD installed inside my MacBook as a replacement startup drive. Using Disk Utility I have tried to erase/overwrite the free space on this HD. The "Erase Free Space" button is grayed out and hovering gives the following message: "Erasing free space not available on this type of drive".
Is there anything I can safely do to erase free space? Since I have deleted a large number of files from the HD to free up space for future work, I am just trying to be security conscious.
An aside: I have wondered if with a SSHD there is less or even no need to erase free space as there might be no residue in the memory locations to permit recovery like there is with a conventional HD, but this is speculation on my part.
Thanks, John

A Solid State Device never writes to the same place that you read the data from. The SSD hardware logic always allocates a new pre-cleared sector and writes to that sector, and the hardware maps that sector to the logical offset for the previous sector. The previous sector is released to the SSD hardware to be pre-cleared at some future time for reuse as a place to write.
So zeroing SSD storage just reduces the life of the drive without actually zeroing the data you desire.
If Mac OS X is detecting that your SSHD has an SSD component, it will not do anything to shorten the life of the SSD component by doing things that are not doing what you expect (aka securely erasing data, which the SSD will NOT be doing).
If you are using an SSD type device, the ONLY way to make sure deleted files are secure after deletion is to enable FileVault so that the entire disk is ALWAYS encrypted so that deleted files are just random bits to anyone trying to access the data without the disk encryption keys.

Secure Erase Free Space

Secure Erase Free Space Failed
Secure Erase Free Space failed with the error:
Couldn't create temporary file.
Hello, I own a 15" Macbook Pro 2011 Late model but I recently replaced the hard drive with SSD and upgraded the memory to 16gb. It was working fine for about 4 months and now sometime it freezes while browsing or even opening an application. I had to restart the macbook and sometime I would get a white screen. I was able to get by the white screen by restarting constantly. I am afraid to shut this macbook down and end up with a white screen. While I got through the white screen, I was able to use the disk utility and got this message when I was cleaning up free space. My SSD has 431.82 GB free of 478.89 GB. Can anyone tell me where do I locate the temporary file or is there something else I need to fix? Please let me know. Thank you.
Vincent

I understands that.
But heres what Im talking about

I need to erase free space on my hard drive. But when I am in disk utility the format and name are pale as is the erase free space button so I cannot erase free space.

My start up disk is full. I have been through my computer and erased a lot of music and video to free some space. I then went to disk utility to erase free space and find that the erase free space button is pale and therefore won't work. Nor can I select or deselect MacOS extended journaled.
Advice please?!

Recovering Disk Space
If you have less than 20% disk space then it is time to roll up your sleeves and search for what you can delete and what you can offload to another disk.
If you have less than 10 GB you definitely need to delete or offload some files or purchase a lager disk or SSD (see below). You may want to maintain at least 20 GB of free space so when your disk starts filling again it will have some room before it hits that 10 GB mark again. More headroom is better. If you let the space fall much below 9 GB you might not be able to boot your machine.
Initial easy steps to gain disk space:
- Delete all files in the Downloads folder.
Empty the Trash.
- Start iPhoto.
Empty its trash.
Restart.
- Restart in Safe Mode:
Restart the computer.
As soon as you hear the chime press and hold the right shift key.
Be patient. Hold it down until you see the Apple icon.
Empty the trash.
Restart in normal mode.
- Delete "Recovered Messages", if any.
    Hold the option key down and click "Go" menu in the Finder menu bar.
    Select "Library" from the drop down menu.
    Library > Mail > V2 > Mailboxes
    Delete "Recovered Messages", if any.
- Empty the Trash.
- Restart.
- Re-index your system disk (Macintosh HD):
http://support.apple.com/kb/ht2409
Time Machine Snapshots:
If your disk is 80% full that is normal. Time Machine uses up to 80% of the disk space for local snapshots. To get rid of these snapshots simply plug in your Time Machine backup drive and run a backup. See About Time Machine's 'local snapshots' on Mac notebooks: http://support.apple.com/kb/HT4878 and What are Local Snapshots? http://pondini.org/TM/30.html .
If you are concerned that the “Other” category of disk usage is taking too much space and for information on deleting files then look here: https://discussions.apple.com/docs/DOC-5142
Backup:
Run a Time Machine (or other) backup since you are about to delete and move files and you may need to recover from any inadvertent mistakes or decisions. You will need one external hard drive for your Time Machine (or other) backup and a second if you plan to offload some files. (See suggestions for where to purchase hard drives at the end of this message.)
For more about backups:
Time Machine Basics: http://support.apple.com/kb/ht1427
Most commonly used backup methods:
https://discussions.apple.com/docs/DOC-3045
Methodology to protect your data. Backups vs. Archives. Long-term data protection:
https://discussions.apple.com/docs/DOC-6031
Deleting files:
Then use the free application OmniDiskSweeper http://www.omnigroup.com/more to explore your volume in descending order by size so you can attack the problem from the top down, deleting the largest unwanted files first. Delete with caution and do not delete any system files. Remember to empty the trash after trashing the files.
Additional reference on freeing disk space:
http://pondini.org/OSX/DiskSpace.html
Offloading files:
Consider moving some of the no-often-used large files or directories to an external disk. Use ODS again to find them. As noted above this will be at least your second hard drive. Your first one(s) is/are for your Time Machine (or other) backup(s). Do not offload files onto a Time Machine disk.
Format the second drive as Mac OS Extended (journaled). Using OWS to find large files/folders and copy them from the system drive to the external hard drive and delete them from your internal drive.
Then  > System Preferences > Time Machine > Options… > Remove the offload HD name from the exclusions list.
Now both your system disk and your external offload disk will be backed up onto your Time Machine disk.
From: http://www.thexlab.com/faqs/freeingspace.html
To move your iTunes Music folder to another disk or partition:
To change the location of your iTunes Music folder, carefully follow the instructions in the AppleCare® Knowledge Base document "iTunes for Mac: Moving your iTunes Music folder."Additional information can be found in iTunes Help.
http://webcache.googleusercontent.com/search?q=cache:http://www.thexlab.com/105/ 00000849.html
Laptop users may want to consider having two iTunes libraries: a small library of current favorites on their computer, while their complete library resides on an external hard drive. Utilities like iTunes Library Manager enable you to easily have multiple iTunes libraries you can use with your account. https://www.macupdate.com/app/mac/7689/itunes-library-manager
To move your iPhoto Library folder to another disk or partition:
To move the iPhoto Library folder to a new location, employ the instructions in the AppleCare Knowledge Base document from http://support.apple.com/kb/PH2506 corresponding to the version of iPhoto you are using. Additional information can be found in iPhoto Help.
Laptop users may want to consider having two iPhoto libraries: a small library of current, favorite photographs on their computer, while their complete library, or archives of older photos are saved on an external hard drive. Utilities such as iPhoto Buddy and iPhoto Library Manager enable you to have multiple iPhoto libraries that you can use with your account.
https://www.macupdate.com/app/mac/12175/iphoto-buddy
https://www.macupdate.com/app/mac/7158/iphoto-library-manager
Hardware — Bigger disk/SSD:
If your system has upgradeable storage then if you are still tight on disk space consider larger storage. If you have a disk consider replacing it with a one TB disk. Check out a one terabyte HGST 7K1000 7200 rpm, SATA III drive from OWC http://eshop.macsales.com ($100). If you have an SSD consider increasing its capacity to 240 or 480 GB. A standard 240 GB SSD would cost from $200 to $280. See OWC and Crucial: http://www.crucial.com/ for options. OWC sells 120, 240 and 480 GB SSD upgrades for MacBook Airs. A 240 GB upgrade costs $265.   http://eshop.macsales.com/shop/SSD/OWC/ . If your Mac is under warranty or AppleCare replacing the SSD will void the warranty.
PlotinusVeritas gives some great suggestions for purchasing external hard drives in this thread:
https://discussions.apple.com/thread/5602141?tstart=0

Disk utility taking forever to "Erase Free Space"!

i am trying to speed up my macbook so i read on http://www.makeuseof.com/tag/how-to-speed-up-your-mac-without-spending-any-cash/ that one way to speed up a mac is to "Erase Free Space" and when i did it, it was working fine but now its been "Creating Temperary File" for like 10 minutes and all of my HD is filled up now when i had like 50 GB open before i did this! i cant take a screen shot because when i do, it says it cant save it because there isn't and space open on my HD! help!!!!

guitar4542 wrote:
i am trying to speed up my macbook so i read on http://www.makeuseof.com/tag/how-to-speed-up-your-mac-without-spending-any-cash/ that one way to speed up a mac is to "Erase Free Space"
that advice is nonsense. there is absolutely no difference in speed when writing to a space written over by zeros as erase free space does.
and when i did it, it was working fine but now its been "Creating Temperary File" for like 10 minutes and all of my HD is filled up now when i had like 50 GB open before i did this! i cant take a screen shot because when i do, it says it cant save it because there isn't and space open on my HD! help!!!!
what you see is normal. erasing free space takes all of the free space on the drive, temporarily puts it into one huge file and writes it over with zeros. that file is then deleted. while the process takes place (and it can take a very long time). you can't use the computer because you have no free space on the hard drive.

Erase free space can't be selected or "erase" is not available

Hi
Today I found that Erase free space can't be selected or "erase" is not available , and I don't know !
I need to get free space ,I know its not a good idea but I need to do it .
So please help me ,if there is something wrong on my mac
Teach me step by step how to show that button ON
Thanks a lot

Please note that "erase free space" does not create free space. It just makes all the bits in the existing free space the same (so that nobody can recover data from the files that used to be there).
Knowing that, do you still need to erase free space?

"Erase Free Space"- DU Not Responding?!

     Started "Erase Free Space" in disk utility about 36 hours ago. I had nearly 1TB of free space which I knew was more than the usual amount someone has when they perform this task but I was attempting to speed up game playing as after a year or so, excess of deleted saved games and game data has gradually slowed game performance down some. I read that this might help so I ran it...
     It took 24 hours to do the initial run through up until the "creating temporary secondary file" notification. It looked as though it was about to complete and I received the usual error message that apple says to ignore about no remaining free space or something to that effect. However, out of nowhere the spin wheel started, the Disk Utility window went grey and everything seemed to have frozen.
     After reading several peoples experiences with things like this I was confident that it would resolve in a few minutes, maybe half an hour even and then most likely resolve itself. It was late so I went to bed and when I got up it was still in the same place as I left it...greyed out and spin wheeled.
     So then I went to the Activity Monitor to check the Disk Usage as I knew that I could view the progress through that. As far as I'm aware, after creating the temporary file, as it already did, it is supposed to start looking like free space is "disappearing" as it puts the recently overwritten free space into its newly created temp file and then eventually deletes the file.
     Problem is, the Activity Monitor shows the Disk Utility as "Not Responding" along with Safari and Mail having the same message, yet at the same time I see the free space on my HD SLOWLY (20-100kb/s) doing that "dissapearing" act. So is the Disk Utility doing its job? Is it hung up some how? If it is working then why is it moving at such an incredibly slow rate? Should I be concerned or take some sort of action or just wait while this resolves itself in who knows how long from now?
Advice on this would be very much appreciated as I am not a very experienced Mac user.

apple customer 1 billion wrote:
There aren't that many files to lose in the long run. It's more a matter of avoiding the risk out of convinience for not losing the few that I have. So correct, I have no back up since there isn't much to back up, hence the nearly 1TB of overwritting free space in the first place. Unfortunately, I realized just how long this process takes after I began it, and now it seems to late...
If I did restart, what would likely happen?
Possibilities I've come across:
1.won't be able to log in because theres no more free space
2.I'd have to search for the temp file and manually delete it (provided I had some extra space to do it)
3.might lose all data and have to reinstall everything
Could be any or all 3
Is there a safe way to either:
1.Restart with little to no complications listed above
2.Safely end this task without some sort of unfixable complication occuring
3.Boost its processing so that I can resonably wait it out
There may not be, but I might as well check around before I go straight to Restart is what I was thinking.
No, no and no unfortunately, patience or a leap of faith are the choices

Does OS X 10.2 has the secure delete option & erase free space

Hi All, I have an old iBook G4 1.42ghz with 1GB ram and I am thinking of putting an old disk of 10.2 onto it as I always liked OS X 10.2.
I just can't remember of this verion of OS X has the secure delete option in finder when emptying trash and also does it have the abilty to erase free space with zeros etc..

What OS 10.2 disc are you planning to use to install 10.2. If it's from another model Mac, it won't work.
 Cheers, Tom

Disk Utility - Erase Free Space - Creating Temporary File Freeze

I used "Erase Free Space" with Disk Utility after trashing several files I no longer wanted on the hard drive or recovered. I used "Zero Out Deleted Files" option. It took over 12 hours before an error message appeared "Your start up disk is almost full. You need to make more space available on your start up disk by deleting files." I thought that was what I was doing. Disk Utility continued but got stuck on "Creating Temporary File." I force quit Disk Utility after several more hours. I had to manually shut down the computer because the restart command wouldn't work. It rebooted and appears to be OK. Evidently, this temporary file consumes significant amounts of disk space. This is an older iMac with 10.4.11 (18 GHz PowerPC G5) - I know, pretty old but I still have OS 9 on it and several files I need to extract before I trash it.
1. Should I do nothing? The iMac seems to be working fine.
2. How do I know if this Temporary File exists and consuming space? Spotlight doesn't find it. Where is it?
3. Is my start up disk in fact almost full? How would I know that?
Thanks!

Then I would not do any secure erasing. It's exceptionally time consuming and unnecessary. Before you take it in for recycling boot it from your OS X installer DVD. Do this:
Drive Partition and Format
1. Boot from your OS X Installer Disc. After the installer loads select your language and click on the Continue button. When the menu bar appears select Disk Utility from the Utilities menu.
2. After DU loads select your hard drive (this is the entry with the mfgr.'s ID and size) from the left side list. Click on the Partition tab in the DU main window.
3. Under the Volume Scheme heading set the number of partitions from the drop down menu to one. Click on the Options button, set the partition scheme to GUID then click on the OK button. Set the format type to Mac OS Extended (Journaled.) Click on the Apply button and wait until the process has completed.
4. Select the volume you just created (this is the sub-entry under the drive entry) from the left side list. Click on the Erase tab in the DU main window.
5. Set the format type to Mac OS Extended (Journaled.) Click on the Security button, check the button for Zero Data and click on OK to return to the Erase window.
6. Click on the Erase button. The format process can take up to several hours depending upon the drive size.
A one-pass Zero Data option is all that is required to prevent access to your erased files.

Trouble with Disk Utility, Erase Free Space

Hello,
I have (had) a 120GB HD w/ about 53GB free. I had trashed some large files and thought I'd try the "Erase free space" option in Disk Utility.
I ran it per the help file: seleced Macintosh HD, Erase Free Space, using the "Zero Out Deleted Files" option. It got started, created a temp file, then told me it would take about 31 minutes. As it neared completion, I was presented w/ a Dialog: Out of Free space - or smthg to that effect.
Per the help file, which said I might be presented w/ such a warning but that I could ignore it, I clicked "OK".
Then the computer chugged along for another hour or so, never finishing. Finally I clicked the "Skip" button, and it chugged along for another 30 min. or so, never making any progress in "skippin" in the status bar. I finally just quit Disk Utility.
Now I'm showing a completely full HD. I've restared, but the same thing. I've tried to run Erase Free Space again, but it gives an error "Could not create temp file" - I'm assuming b/c it needs free space to do the task, and it thinks there is none. So...
...How do I get my free space back?
Thanks in advance...

There's probably a huge temp file somewhere, maybe in a folder in your Trash. Do a search for a huge (multi-GB?) file (it might be an image file) that looks suspicious.
The only reason to use erase is for security purposes, and doesn't do anything in the normal course of computer usage. Erase actually writes data to your remaining file space (as you have discovered with no space left) and then trashes that data (or not, in your case).
P.S. In future you should post this kind of topic as a question so people will know it is something that needs answering rather than being a comment.
Message was edited by: Limnos

"Erase Free Space" work-around for non-apple ssd

for those of you attempting to "Erase Free Space" per knowledge base article:
"OS X Lion v10.7.3: User account passwords appear in log files for Legacy FileVault, and/or network home directories"
quote:
"6. Open Disk Utility.
7. Select your OS X Lion volume on the left.
8. Click "Erase Free Space…".
9. Select the Erase Free Space Option you want and click "Erase Free Space". Enter admin name and password if prompted."
but instead seeing a grayed out "Erase Free Space" in Disk Utility?
you can perform an "Erase Free Space" by using WipeFS app by Jonathan Clark which can successfully perform a DoD (Department of Defense) wipe for digital media, apple's Disk Utility doesn't do this anymore with non-apple solid state drives (ssd)
references:
https://support.apple.com/kb/TS4272
http://itunes.apple.com/hr/app/wipefs/id484887048?mt=12

...but instead seeing a grayed out "Erase Free Space" in Disk Utility?
See,
Mac OS X: About Disk Utility's erase free space feature
which says,
Note: With OS X Lion and an SSD drive, Secure Erase and Erasing Free Space are not available in Disk Utility. These options are not needed for an SSD drive because a standard erase makes it difficult to recover data from an SSD. For more security, consider turning on FileVault 2 encryption when you start using the SSD drive.
Also google "erasing space on ssd".
Bottom line, it is not something you want to do to a ssd.

Help! iMac performing in erase free space for over 14 hours!

How long should 7-pass 'erase free space' of 69.9 GB take?
I'm giving my old iMac G4 to a young relative. After completing 'erase and install' of OS 10.4, to be sure data would not be easily accessible, I read a few threads in the Installation and Setup forum and decided to do a 7-pass erase of free space.
The message in the Disk Utility window counted down from 8 hours and then switched to "secure erasing file". The blue progress bar doesn't appear to be progressing but is stuck about 1/2 cm from the end.
It's now been going for 14 hours. This seems an extra-ordinarily long time, 'though, for all I know, zero-ing out could take 2 hours. Thinking back, I clicked on 7-pass twice, once via 'security options' then via 'erase free space'. Was that a major mistake?
Is 14 hours too long? And, if so, is it too late to click on 'skip'?

Well, I pressed 'skip' and little changed except that it reported "skipping", whatever that means. So I took courage in both hands, as it were: one to press 'quit' and the other to press 'continue' and ignore the warning that quitting could cause irreparable damage to the HD.
As far I can see, no problem but I'm going to run Drive 10 before I erase-and-install OS X again just so that I can command-Q setup assistant and leave my young relative to set it up for herself.
Many thanks for your help, both Toms too. I guess this question can be logged a 'solved'.
Anne

Erase free space function of Disk Utility

Hi all,
I've read some of the discussions about the problems that can result from using Disk Utility to permanently delete items that have been emptied from the Trash (and which were not "securely" emptied). Before I use the Disk Utility function, I'd appreciate some advice:
1. I have an iBook G4, running Mac OS 10.4.11. My hard disk has a capacity of 55 GB with 30 GB available. Does the capacity available matter, and is mine sufficient?
2. Will I be given an option on overwriting the files 0, 7, or 35 times, and should I choose 7?
3. How long is this operation likely to take?
4. Shall I just start the operation and then not touch the computer for a few hours, or overnight, and hope for the best??
5. A final question (a stupid one, I hope!) -- only those files which were put in the trash will be deleted, right?? Not anything else?!
I am quite worried about taking the step because, if things go wrong, I won't have a means of contacting the Apple support forum as this is the only computer in our household.
I am planning on giving this iBook to a nephew in six months or so, and am gradually cleaning it up for that purpose. But I'm not ready to "zero it out" entirely and I am hoping not to lose anything currently on my hard drive following the "erase free space" operation, or to have to reboot from the original CDs.
If the operation is successful, I will then remember to always use the "Secure Empty Trash" option when deleting future files. I'm assuming that, if I do that, I should have no concerns about giving the laptop away -- correct?
As you can tell, I'm not very computer savvy, and I'd be very grateful for help. Thank you!

Open Disk Utility, Highlight your drive on the left, then on the right bottom you'll see Verify Disk & below that Repair Disk grayed out because you can't reopair the HD yo're booted from, if it does need Repair...
1. Insert the Mac OS X Install disc, then restart the computer while holding the C key.
2. When your computer finishes starting up from the disc, choose Disk Utility from the Installer menu. (In Mac OS X 10.4 or later, you must select your language first.)
*Important: Do not click Continue in the first screen of the Installer. If you do, you must restart from the disc again to access Disk Utility.*
3. Click the First Aid tab.
4. Select your Mac OS X volume.
5. Click Repair. Disk Utility checks and repairs the disk."
http://docs.info.apple.com/article.html?artnum=106214
Then try a Safe Boot, (holding Shift key down at bootup), run Disk Utility in Applications>Utilities, then highlight your drive, click on Repair Permissions, reboot when it completes

Disk Utility Erase Free Space Option Nonexistant

Have an iMAC 1 GHZ PowerPC G4 256 MB DDR SDRAM OS 10.3.9. According to various google results I should be able to call up Disk Utilities>Partition>Erase>Erase Free Space. Its not there. (Its exactly where it should be on a nearby G5 running 10.5.8.).
It will allow me to erase the entire disk or either of two partitions but the Erase Free Space isn't just grayed out, it is completely missing.
1) The hard drive was partitioned at some point in the past I think to get around some admin thing. One partition has 51 out of 60 GB filled, the other has 12.4 of 16.3 GB filled.
2) Don't ask about the admins, my Entourage has been broken for 9 months - I am not joking.
3) My computer knowledge is spotty - you've been warned.
Help!

Try starting the iMac in Target Disk Mode while attached to one of your newer computers with a firewire cable. This basically makes the iMac an external hard drive. I've not tried this but you should then be able to use a newer version of Disk Utility on that drive.
[How to use FireWire target disk mode|http://support.apple.com/kb/HT1661] includes description of hardware and software requirements.
[What to do if your Mac doesn't enter FireWire Target Disk Mode|http://docs.info.apple.com/article.html?artnum=75414], also read about [Open Firmware Password Protection|http://www.apple.com/support/downloads/openfirmwarepassword.html] which can disable Target Disk Mode.
I'm not a technician but I don't think it "misses" areas, it's just more a matter of covering up what was written there before. Think of it as you write something on a piece of paper, then erase it and write something down in the same space. If you look closely you can see what was written there before. Now erase that again and write something else. It'll be pretty difficult to make out what was written there the very first time. Do that 7 times and it will be very, very, very difficult. Do that 32 times and it will be impossible. However, all that erasing and writing will take its toll on the paper and take a long time. I'd say anything more than a erase once would really have to be justified by very sensitive data. Anybody wanting to recover the data would have to use pretty specialized equipment.

'erase free space' not secure - it doesn't seem to work?

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