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

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I used the "erase free space " option in disk utility and now my imac says the disk is full and wont let me download songs. please help!

i used the "erase free space " option in disk utility and now my imac says the disk is full and wont let me download songs. please help!

You could try repairing permissions with disk utility, I don't think you will have the option to repair the drive but you could verify it.
This may help you delete the files that DU made but did not remove when erasing the free space.
http://macosx.com/forums/mac-os-x-system-mac-software/317204-no-disk-space-after -failed-disk-utility-erase-free-space.html
When you get your SL disk it will not have the iLife applications, that would have been on the second install disk that should have been with the computer. I forget which version of iLife you will need for SL but I think it is this http://www.amazon.co.uk/Apple-iLife-Single-User-Mac/dp/B003XKRZES/ref=sr_1_1?ie= UTF8&qid=1409607702&sr=8-1&keywords=apple+ilife+11
A search of the forums will confirm or deny this.
As to whether a clean install will cure your problem, i.e. partition the HDD and install I would expect it to be yes, but there are no guarantees it is an old machine.

Help please - message after using the Erase Free Space function in Disk Ut

Please help. I've been using my Mac Mini for 6 months and decided I wanted to securely erase previously deleted files, and found the Erase Free Space facility in Disk Utilities. So I chose the option "7-pass Erase of deleted files", and left my Mac Mini to do its business.
At the end, I got the message that my startup disk is full, but ignored that message because I understand that's normal when free space has been deleted.
After doing a Restart, things seem to be running smoothly, but I have a Warning message which reads
Warning. The following disk images failed to mount:
Image: EFTFile1.sparseimage Reason: corrupt image.
What does this mean, please, and what do I have to do, if anything?
I'm completely new to this, so please explain clearly.
Thanks everyone!!

Hi again, i've resolved the problem, thanks. It was my inexperience that was helping confuse the issue.
Sorry to have taken your time. Thanks again for your input.

Help using "erase free space" feature in Disk Utility

If I try to "erase free space" on my hard drive, the task never completes, and a temporary file is created, which can be deleted upon restart. If I start up from the Tiger Install DVD to wipe the free hard drive space, will I still have this problem or will it work properly?
G5 Dual 2.3 GHz Mac OS X (10.4.6)

So how much "free space" for a Temp file do you need to even use "Erase Free Space"? I have 111G available (120G drive), and I have 50G "free space", and it uses up all my space for a Temp File, then won't proceed unless I "clear more room on your startup drive". I need over HALF the drive empty to even use "Erase Free Space"? It would be nice if Apple told us before we started the long process.

What does the "Erase Free Space" function do?

in the disk utility, there is an option to erase free disk space.
what exactly does this do?

From Disk Utility Help:
"When you delete files by emptying the Trash, Mac OS X deletes the information used to access the files but doesn’t actually delete the files. Although the disk space used by deleted files is marked as free space, deleted files remain intact until new data is written over them. As a result, deleted files can be recovered.
You can use Disk Utility to erase the free space used by deleted files by having zeros written over the space once, 7 times, or 35 times. If you have a lot of free space on your disk, overwriting the free space several times can take a long time.
Erasing free disk space does not erase the other files on your disk."
charlie

Disk Utility: erasing free space

I read a recent magazine feature about file security and, based on its advice, clicked the Erase Free Space button in Disk Utility to overwrite the free space on my hard drive.
Everything ran smoothly until the last minute, when the countdown switched to "Creating Temporary File". After five minutes, a dialog box appeared warning me that the start-up disk was almost full.
I'm not concerned that I might lose material on the start-up disk since I have an external drive as a complete bootable back-up of the hard drive. But:
1. What's is being created in this temporary file and why?
2. How do I get Disk Utility just to erase the free space next time and not bother with the temporary file that seems to fill all the space (and more) that has just been cleaned?
Thanks in advance.
PowerMac G4 867MhZ Mac OS X (10.4.6) iGB RAM
PowerMac G4 867MhZ Mac OS X (10.4.6) iGB RAM

You're Welcome Norman!
I'm happy that I could help!
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This info, and more, can be viewed by clicking on
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ali b

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 vs Reformat Hard Drive

I am getting ready to sell my computer. In the past I have had troubles when I reformatted my hard and then reinstalled the OS. If I use "Erase Free Space" from the Disk Utility and choose 7 pass overwrite should I be confident that all deleted personal information will be securely removed?
Thanks
12" PowerBook G4 Mac OS X (10.4.8) 768 MB RAM, Superdrive

It would be simpler, not to mention much, much faster, to do an Erase and Install of OS X. If you've had problems with the hard drive in the past, then I suggest doing the following before installing:
Extended Hard Drive Preparation
1. Boot from your OS X Installer Disk. After the installer loads select your language and click on the Continue button. When the menu bar appears select Disk Utility from the Installer menu (Utilities menu for Tiger.)
2. After DU loads select your hard drive (this is the entry with the mfgr.'s ID and size) from the left side list. Note the SMART status of the drive in DU's status area. If it does not say "Verified" then the drive is failing or has failed and will need replacing. Otherwise, click on the Partition tab in the DU main window.
3. Set the number of partitions from the dropdown menu (use 1 partition unless you wish to make more.) Set the format type to Mac OS Extended (Journaled, if supported.) Click on the Partition button and wait until the volume(s) mount on the Desktop.
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, if supported.) Click on the Options 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 will take 30 minutes to an hour or more depending upon the drive size.
After formatting has completed quit DU and return to the installer. Now proceed with the OS X installation. When the installation has completed DO NOT RESTART. Instead simply shut down the computer. When the new owner starts up the computer it will automatically start up in the Setup Assistant as if new out of the box.
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"Erase Free Space" in disk utility, writes a large file?

While poking around in disk utility I came upon the 'Erase Free Space" function so I decided to try it out and see how it worked. I chose the medium security setting and let it run. After a while I stopped it because it was going quite slowly. Afterwards I noticed that about 25gb of previously free space was gone from my HD. Did it write a backup file?
I tried looking for a file but "find" in finder coldn't seem to locate any files written during that time period.
any direction to recoup the space is greatly appreciated.

OK, thanks guys.
Sometimes the simplest things...
Now if I were at the office working on something on a windoze machine a restart would be the first thing I would try, you have to restart twice a day even if the machine is working properly!
I however, rarely shut down my Mac. Unless there is a thunderstorm or I am going away, or I've performed an update, the machine stays on/sleeps.
Apparently as an "erase free space " is being performed the space is being used as zeroes are written. When I allowed it to complete the space returned. However; the space that was consumed during the aborted try was still not availible.
Only after a restart did the space become shown as being free.
This has been great since I now know of 2 more helper apps. Tinker Tool allows me to see hidden files and change other prefs not availible natively. OmniDiskSweep quickly check file on the HD.
Thanks for your help, and if there were votes still, I'd use them all!
-T

Failed Erase Free Space NOW missing all free space

I just recently performed an Erase Free Space from the Disk Utilities application. It failed and now I am missing all my free space. Can someone please help me correct this problem.
I did post this same question in another Forum. I wanted to make sure I posted it in the correct place.
Thank you,
Shannon

I think that a file is created that is the size of the free space, and then written over several times and then deleted. There may be a very large file lurking somewhere on your hard drive. You might want to try using a free utility like Whatsize to look for a large mysterious file, and if you find one then just delete it. Good luck.

Disk Utility - Erase Free Space

Hey Forum,
I am using mac snow leopard on my macbook and I wanted to erase the free space on my hard drive, so is the zero-out free space enough, or do I need the 7-pass erase free space. I just wanted more disk space, thats it. So can anyone tell me what are each options for? And do i need to 7-pass erase if i just wanted more disk space?
I await your favorable replies.
Thank you.
Regards.
Ala.

As The hatter says, the erase free space option has nothing to do with creating more free disk space -- the space is already free.
If you are confused about this, just open Disk Utility to the "Erase" tab & click the purple question mark at the bottom of the window. This will open Disk Utility Help to the topic *Erasing disks*. Refer to the last subject, *Securely erasing empty space* & if necessary click the link below it to go to the help topic *Erasing free disk space*, which explains this function in more detail.
FWIW, should you ever need to use this security function, a one pass secure erase is probably adequate to make the data unrecoverable.

SSD - Disk Utility - Erase Free Space

Hi Community,
does the function in disk utility, which erases the free space by writing zeros into it, in context to a SSD drive the same like a block refresh which some drive vendor utilities does to increase the write performance? Or is a block which contains only zeros not really empty for the SSD controller?
Thx & Bye Tom

I am guessing a little here, but I suspect that "Trim" support ensures that data in free space can't be reaccessed once the files are deleted.
Another guess is that erasing the SSD free space may not be a great idea from the point of view of unnecessary writes and also filling the entire usable space up with what may appear to be data.
We are also discussing this subject in a German newsgroup and there we came to the result that the only way to inform the SSD-controller that the content of a specific block is invalid, is either to overwrite a specific logical address, so than the controller knows which physical blocks are invalid or to send the TRIM command.
To write zeros into the empty space is from the controllers point of view only content and will result in a full SSD drive afterwards. As longer I think about this as more I belief that this is correct and the use of the disk utility to refresh a SSD drive isn't the best idea... ;-)
Bye Tom

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
"Secure Disk Erase failed with the error: Couldn’t unmount disk."
But "erase free space" seems to work...
What can I do? I'm erasing as I'm giving the drive to someone else and I wanted to wipe it clean.
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!

Time Capsule full after a "Erase Free Space" using Disk Utility

Hello,
I am facing some issues related to my Time Capsule.
Reviewing my past, I had a lot of backups on this, using Time Machine and it always worked pretty well. But after deleting some backups manually to reclaim disk space, this was not exactly freeing it.
Searching in the forum here, I saw that I could mount the backup sparsebundle image and map it into the Disk Utility. This always worked greatly too both for disk checking and reclaiming the space back.
The problem starts on the last Friday when I performed the operation again, but it started using the whole free space that I had and did not give it back.
Studying the case I found that it creates a temporary folder to store the file it creates to write the byte 0 on the disk. This file actually resides in the sparsebundle image and therefore I can see the file with 200GB, for example, in the Finder, this is a split in bands (8MB) just like the backup is. After the disk gets full, the Disk Utility should delete the file properly and give me back the space safely.
Right now my Time Capsule has 0 byte free and I can't do anything on it beyond redo the the Erase Free Space operation. When I do it, it starts writing the temporary file again and the problem repeats itself.
I know that if I backup the data and really erase the disk, I'll get it back, but this is not an option for me because I want a smart solution for this.
The only thing that changed between when it worked and now is the 10.5.6 update that I made and I'd like that it's not the root of the issue.
Is there any suggestion or general stuff I could do to fix it?
Did anybody already face the same issue?
If anyone needs more details to help me out of this, just let me know.
Thanks and regards,
Eduardo

Just another thing to add, I'd like a good solution for this as the redo operation from Disk Utility takes around 2 days and then it just "dies".

7-pass, or zero out-Disk Utility Erase Free Space

Hey Forum,
I want to clear my erase free space on disk utility. And I am confused, whether to use 7-pass or zero-out? Any suggestions which one to use. Is zero out enough, or is 7-pass too much, any suggestions of whether to use either of them is appreciated, thank you.
Ala.
P.S. What are zero-out, 7-pass, and the 35 thing for and their differences?

There is no need to post the same question twice, especially in the same forum.
Regarding what you can find with Google, an overly simplified or out of date treatment of the topic may lead you to the wrong conclusions. For example, the DoD 5220-22M standard is obsolete (& never recommended a 7 pass erase to begin with) & the 35 pass erase was intended for old, pre-2001 drives.
For modern ATA drives like you will find in any Mac capable of running Snow Leopard, one or at most a few zero data passes will do all any software-based secure erase method can do.
If you need verification of that, refer to the Epilogue section of Secure Deletion of Data from Magnetic and Solid-State Memory, the seminal paper on the subject by the author of the 35 pass method.

Erase free space function of Disk Utility

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