Does Secure Empty Trash Accomplish the same task as Running disk util to wipe free space

Does using the secure empty trash option accomplish the same task as running disk util to eliminate free space from old deleted files?   I'm currently running the 7 pass deal on my late '12 iMac.  Says its gonna take 7 hrs.   Can I use safari or iTunes  while the Big Mac works its magic?

Does using the secure empty trash option accomplish the same task as
running disk util to eliminate free space from old deleted files?
No.
Finder > Empty Trash just tells the file system that those areas on the drive are now available for overwriting with new data. Data deleted off hard drives can be recovered if this method is used before it's overwritten with new data with special software.
Finder > Secure Empty Trash runs a 7x pass military approved overwrite only on the deleted files in the Trash, works for hard drives only.
Disk Utility > Erase Free Space creates a huge file that takes the remaining free space on the volume selected and either writes zeros or 7x pass, then confirms it and then removes the file.  Takes a long time to complete, do not interrupt.
This can be used if one forgets to use Secure Empty Trash or wants to scrub caches or other files that don't necessarily go to the Trash for user deletion, such as program files that self delete and download cache files etc.
Only works for hard drives and there is no recovery possible for nearly all users. Those with special expensive magnetic equipment can possibly recover data off a zero pass, but not off a 7x overwrite.
The zero erase free space can be also be used to pre-eliminate potential unknown bad sectors on hard drives before wanted data is written to them, thus preventing future issues with data retention on hard drives.
Disk Utility > Erase - (not moving the slider) will erase all data on the volume or partition selected, including wanted data. It just tells the file system the deleted data is ready for overwriting. Thus can be recovered using special software before it's overwritten on hard drives only.
Disk Utility > Erase w/Security Option - (or moving the slider from the left) will secure erase all data on the volume or partition selected, including wanted data.
It can vary on the operating system version used from zero pass, to 3x overwrite, to 7x overwrite to 35x overwrite (old version for days past of smaller drives, don't use on newer larger drives as it will take weeks to finish.)
Secure erase methods are used to secure erase private data off of hard drives only, doesn't work for SSDs.
For secure data deletion off a SSD or any flash media, it's NSA advised to grind it into a fine powder.
How do I securely delete data from the machine?

Similar Messages

  • Why does SECURE EMPTY TRASH take so long (several days)?

    I am using OS 10.3.9. I didn't empty the trash for quite a while, and several days ago clicked SECURE EMPTY TRASH. The emptying process began but has not finished even now! Does it take THAT much longer when one uses SECURE EMPTY TRASH? I see that the little message window for Trash says:
    Item to delete: 114,158 This number hasn't gone down now for several minutes.
    Several times I have stopped the Empty Trash process to shut the computer down or just because I wanted to stop it, but it seem to me that after "Emptying the Trash" has been going on for so long, it ought to be finished by now. I welcome any sunlight you can shed on this. Thank you.
    — Lorna in Southern California

    When you choose to Secure Empty Trash, the system
    must overwrite the area where those items area a
    minimum of 7 times for it to be considered secure.
    When you have that many files in the Trash, this can
    take quite some time.
    So, unless you have something that is confidential in
    the Trash, your best option is to Empty Trash
    normally.
    Mulder
    If my answer helped solve your problem, please
    consider awarding some points. Why
    Reward Points?
    OK, and thank you. You have answered my question; I now won't be worrying that something is awfy. The Secure Empty Trash is still emptying and it is down to about 77,000 items. I have clicked the YES, MY QUESTION HAS BEEN ANSWERED button and I appreciate your reassurance.
    — Lorna in Southern California

  • My external hard drive accidentally switched off during Disk Utility's "erase free space" process.  I restarted the external hard drive and Disk Utility, but now I get the "couldn't mount disk" error when trying to finish the erase.  Please help!

    My external Lacie Quadra hard drive accidentally switched off in the middle of "erase free space", and when I switched it back on Disk Utility was hanging.  So I Force Quit Disk Utility and restarted it.  Now when I try to erase I get
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    Also should I use "erase" or "erase free space" if I want to wipe the drive clean?
    Please help!

    Sorry I don't really understand.... there are no partitions on the drive.  How do I repartition it?
    And should I use "erasing free space" or "erase" for wiping clean my drive of everything?  Erase seems to be faster last tiem I tried.
    Thanks!

  • What exactly does "Secure Empty Trash" do?

    There's very little technical detail on the web about this. I'd like to understand exactly what secure empty trash does.
    What method does it use to overwrite?
    How does it deal with temp files?
    Why does it take so long?
    Why, when there's only one file in the trash, does it always claim it's erasing 9 files?
    What other files is it erasing in addition to the visible trash contents?
    Can it work across network connections and external drives?
    Has the method changed in Leopard?
    etc.. etc..
    Feel free to get all technical, if you know the answers!
    Thanks!

    What method does it use to overwrite?
    It writes over the files with 0's.
    How does it deal with temp files?
    Not sure what you mean. It treats any file in the trash the same. Could you elaborate?
    Why does it take so long?
    Because it has to first write over the item with 0's, then delete the item.
    Why, when there's only one file in the trash, does it always claim it's erasing 9 files?
    What other files is it erasing in addition to the visible trash contents?
    It's a bug.
    Can it work across network connections and external drives?
    Yes.
    Has the method changed in Leopard?
    Not that I know of.

  • Does secure empty trash save disk space?

    Secure empty trash takes so much longer than just emptying the trash. Is secure empty trash just used to prevent files from being recovered, or does it actually save disk space on the iMac?

    I am aware that everyone said that it doesn't save any disk space, because I read through the thread.
    HOWEVER.
    I had gotten down to 500 mb of disk space and was going crazy trying to delete photos and movies.
    Finally I read about the secure delete, tried it. It took 24 hours, and then i hat 36 free gigabites.
    THIRTY SIX GIGS OF MEMORY THAT I DIDNT HAVE BEFORE.
    Only thing is I have no idea why, because everyone else says that it doesnt clear space.

  • I clicked on secure empty trash and just lost about 40GB of disk space...

    I had something in my trash that wouldnt delete when I clicked Empty Trash because it said it was in use.
    I looked up on here on noticed people said just to click on Secure Empty Trash when i did that.
    The Secure Empty Trash was starting to freeze up half way so I just clicked on cancel.
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    Try this to find your missing space...
    OmniDiskSweeper...
    http://www.omnigroup.com/applications/omnidisksweeper/download/

  • HT3680 How to get my free space back after quitting the disk utility's erase free space

    Hi,
    I started the DU's erase free space--fastest way method.  When it almost completed, I had a pop up that said that I need to free up disk space.
    So then i was flustered enought to just quit the program because I didnt want to free up disk space and I was frustrated. 
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    Sorry I don't really understand.... there are no partitions on the drive.  How do I repartition it?
    And should I use "erasing free space" or "erase" for wiping clean my drive of everything?  Erase seems to be faster last tiem I tried.
    Thanks!

  • Secure Empty Trash vs Empty Trash, Hangs and Advanced Finder Pref.

    I've had my intel-based iMac for a couple of weeks and I've been getting a frequent hanging trash problem that causes me to restart my Mac far too often. Restarting the iMac fixes it but I don't know what the problem is to begin with. It seems to happen when I have over 10MB in the trash and I choose "Secure Empty Trash."
    While I'm on the topic of "Secure Empty Trash," won't "Empty Trash" do the same thing SECURELY since I've previously checked it off in my Finder Preferences? Is the "double selection" of secure empty trash part of the problem (i.e. selecting it when I go to empty the trash as well as having it selected in my finder preferences)? Any and all help is appreciated.

    Yes it's the same if you choose Secure Empty Trash from the Finder or if you have it selected in the Finder advanced preferences. The thing is electing to Secure Empty the trash may take a lot longer to empty because it does either a 7 pass or 35 pass write over the files and that can take a long time to do for large files.
    As a test it took me just over 3 minutes to Secure Empty a 175MB file.
    Something you should do though seeing as you've had to forcefully shut down your iMac a few times is Run Disk Utilities. Open up Applications/Utilities/Disk Utility select your hard drive on the left and under the First Aid tab click on Repair Disk Permissions then Verify Disk.
    George

  • Secure Empty Trash Hung Up

    I selected "Secure Empty Trash" and the process started. It shows only six files to be deleted. However, it has hung up on those six files, now sitting there doing nothing for over an hour. It won't let me cancel the empty command. It won't let me delete anything else while it's running. It won't let me shut down the computer in a normal fashion.
    How can I get out of this?
    Thanks.
    Charley

    No. It's not necessary, since you've solved the problem.
    See these:
    Basic Tutorials on using a Mac,
    Mac 101: Mac Essentials,
    Anatomy of a Mac,
    MacFixIt Tutorials,
    MacTips,
    Quick Assist, and
    Take Control E-books.

  • Secure empty trash wants to kill all files

    Trying to open up space and speed up my iMac by emptying trash, which has worked fine in the past.
    Now, with 376 items in the trash bin, when I hit "secure empty trash" it tells me it is killing 12K+ files.
    Why is it doing that, and how to I get rid of the trash without erasing the whole disk?
    Addendum: Now it's up to 32K+ files. Does this mean it is trying to overwrite every file I have ever deleted? Also, "Secure empty trash" is the only option available. No plain-vanilla "empty trash" to be found.

    http://www.thexlab.com/faqs/trash.html

  • Secure Empty Trash not 100% safe

    Recently I use finder to enter directly into Firefox's cache files and move all the files into the Trash. Next I use Secure Empty Trash.
    After that, I used Data Rescue II to see what i can find.
    I am very surprised to find most of the images that i have securely deleted.
    I know the best way is to use Disk Utility's erase free space function, but if Secure Empty Trash is going to write the data 35 times over, and still can't get the job done.
    Then using Erase free space's 35 times write-over isn't completely safe too?

    Normally when a file is deleted insecurely, the data isn't deleted at all - the only thing that is removed is the reference to the data in the file catalogue. Overwriting a file even once (let alone 35 times) should prevent recovery by programmes like the one you mentioned that are designed to detect unlinked files and create new catalogue entries for them. Given the above, a few possibilities come to mind that could account for your observations.
    One is that the files you recovered were not the ones you thought you deleted. For example, working with "TextEdit.app", any time a previously saved document is modified, an invisible "autosave" copy is created on the hard drive, intended to preserve any modifications in case the programme or computer crashes. This copy is removed insecurely once the changes are manually saved. If the original is then securely erased, it will be unrecoverable. However, data recovery programmes can easily recover the remnants of the multiple intermediate "autosave" files. I have no idea how "FireFox" works with cache files, but perhaps what you recovered was remnants from previous times you visited the sites that were cached in the files you securely deleted.
    A second, less likely possibility is that your files were recoverable due to a design flaw introduced in Leopard's version of "Secure Empty Trash" (I haven't tested recently so I don't know if the issue has since been addressed). It is possible to configure it so that files are not securely deleted, even when selecting the option. However, such a configuration would not be a random occurrence - basically, a user would have to set it themselves, although malware or a malicious person with access to your account could do the same...
    A third possibility, perhaps related to the second, is that in Leopard, regardless of whether the over-writing stage of "secure empty trash" succeeds or fails for any reason, the process will still continue to the unlinking stage, in effect deleting insecurely. Prior to Leopard, if over-writing failed, the file would not be unlinked, which had at least two benefits: i) since the file was never insecurely deleted, it would not be necessary to initiate a time consuming "erase free space" procedure to ensure that the data was destroyed; and ii) the very presence of the file serves as feedback to the user that the procedure has failed, unlike in Leopard where it fails silently.
    Either way, using "erase free space" shouldn't be affected by these issues. If the file has been deleted (i.e. copies do not still exist in a hidden cache file somewhere), then overwriting "free space" should prevent basic recovery software from restoring it, assuming the procedure is allowed to run to completion.

  • "Secure Empty Trash" Didn't Clear Space on HD

    How can I reallly clear the space formerly occupied by BackUp files?
    When I used "Secure Empty Trash" after putting lots of BackUp files in the Trash, there was no change in the amount of available HD space. I have about 10GB of applications and files on a 60GB HD, so there should be about 45 GB of free space, but there's only 4 GB available.
    FWIW, I've Repaired Permissions (only a few were necessary) and Restarted to no avail. I've used "Secure Empty Trash" to remove another file, and it worked just fine!
    So how can I clear the part of my HD that I asssume is written with random 0s and 1s left by "Secure Empty Trash", not real files?

    John:
    Thanks for hanging in there with me! As you knew it would, WhatSize worked.
    It identified the old Backup files (that the Finder didn't) and transferred them to the Trash. I used Secure Empty Trash delete them. This time it worked correctly and I have space for Backups again, thank-you very much!
    If you have any idea why it didn't work the first time, I'd appreciate knowing it. I've never used it before, so I don't know if it has a repuitation for being buggy or otherwise problematic.
    The name "WhatSize" was a little misleading.... I initially thought it would just do what the Finder's View > Show View Options > Calculate all sizes command does. Some of the comments on the Version Tracker site supported that idea, so as the stubborn Dutchman that I am was reluctant to do something that might make matters worse.
    I also never considered the possibility that using Secure Empty Trash (as I had) would convert files into hidden files..... especially since I've never had such an experience in uising standard Empty Trash in 25+ years of Apple II and Mac use.
    As you expected, I have learned that lots of HD space is devoted to hidden files (that once were visible in the "old days", if I'm not mistaken).
    In any case, I very much appreciate your wisdom and willingness to keep replying when I didn't take your suggestion! Thanks!
    Cheers!!
    Dick

  • Secure Empty Trash doesn't work

    Working in Mavericks on an iMac 27. Secure Empty Trash starts but disappears and nothing is deleted. Is it safe to use Erase Free Space in Disk Utility?

    danimal303 wrote:
    So it won't help me at all. I don't quite see any use for it, a good reason not to use it. But I have some 560 000 files in Trash and they won't budge.
    When you delete a file (without Secure Empty Trash), all the data of the file still exists on the file system free list.  It will remain there until the file system reuses the space.  Erase Free Space is a way to address this, after files have been deleted.
    It is only really useful as a once in a while event, such as someone forgot to use Secure Empty Trash for a file with sensitive data.  And Secure Empty Trash is very time consuming, and worse it is if you have an SSD, this wears out the SSD faster.
    A better approach is to use FileVault so that a deleted file is instantly securely deleted because it was always encrypted.
    Since you are attempting to use Secure Empty Trash, then I would try this from the command line using the 'srm' command.  "man srm"
    srm -f -r -v ~/.Trash/*
    The srm command will perform a secure erase.  The -f will keep it from prompting for approval.  The -r will recurse through and directories of files in the trash.  The -v will display the progress while deleting so you can see how things are going, and have an idea of how much progress you are making.
    Be very careful with srm, as if you point it at the wrong directory it could delete something you care about, or a lot of somethings.
    If there are files that srm -f will not delete, then you bring out the sudo command.  But be VERY CAREFUL with sudo, as you can delete a lot more than just a few files you care about.
    sudo srm -f -r -v ~/.Trash/*
    Password: you enter your account's password here, assuming you are the admin of the Mac.

  • Secure Empty Trash vs. Empty Trash

    I just finished editing many gigs of old video footage and I am ready to delete them. Should I use the Secure Empty Trash-In the Finder (which will most likely take a long time to delete) versus just Empty Trash...I know S.E.T. will completely remove the files which make them unrecoverable. If I delete by using just the empty trash...am I still taking up HD space?
    Thanks...
    Henri

    Hello,
    When you empty the trash, the files are still physically there. But, the space they occupied is marked as available for use. So, they are not taking-up any space. That space is immediately freed, and made available for use by the next program or file that needs it.
    But, because it is stored magnetically, that file can be retrieved by manually (or with a special program) going back and locating where that file was stored and re-assigning a name and a pointer to it.
    The only difference between regular empty trash and secure-empty trash, is that the secure option will immediately over-write that deleted file's space with garbage a couple of times to make it more difficult for someone to recover (or undelete).
    That is the only difference. Otherwise, the space is still storing magnetic information regardless of which method you use. But, it is not wasting space either way. The space is marked as free, and will be used as needed.
    I hope this helps.
    Let us know if you have other questions.
    P.S., if you'd like, go ahead and click the "Helpful" or "Solved" buttons on any of the posts / replies above if you feel they were helpful or adequately answered your question.

  • Hi, Question about secure empty trash. I moved some Time Machine backup files to the trash from an external hard drive. Now I can't secure empty trash. It starts, finds 74,003 files, and does nothing. The external hard drive shows it's empty, but it isn't

    I moved some time machine backup files from an external USB hard drive to the trash. Tried secure empty trash. It counts 74,003 items, then just sits there. The external hard drive window shows it's empty, but the info pane says it only has 50G of memory left. I left the secure empty trash on over night. It did nothing. Ideas?
    Thanks,
    Ron

    Relaunch the Finder, then from the Finder menu bar, select
    Finder ▹ Preferences ▹ Advanced
    and uncheck the box marked Empty Trash securely. Try again to empty the Trash.

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