Erasing Securely in Disk Utility

Erasing Securely in Disk Utility
I wish I could send this directly to the Apple software engineer in charge of Disk Utility, but maybe there is someone on this Forum who is technically very savvy and would stake their reputation on their answer.
I would bet thousands have had this same question cross their mind...
I'm trying to understand the process regarding erasing a hard disk using Disk Utility.
For this example, use a 300 GB hard drive that has the following:
150 GB of readable files
100 GB of files that were sent to the trash and emptied (but not "secure empty trash"… so just their directory info was erased when trashed)
50 GB of never used free space
I'm confused by the wording in the Disk Utility's erase options.
One of the choices is Zero Out Free Space.
Does that mean it only writes zeroes over the 50GB of never used space?
Or does it write zeroes over the 50GB AND the 100GB spaces?
Another confusing choice is Zero Out Data
Does that mean it only writes zeroes over the 150GB of readable data?
Or does it write zeroes over the 150GB AND the 100GB of unreadable data ?
If the latter is true, then the sequence probably should be
erase free space (unless it ONLY writes zeroes to never used space)
then choose
zero out data (assuming it also zeroes the unreadable data too)
Thanks for any help

Perhps I did not make myself clear (or you misread a verb or two).
I did read your link,but it does not clarify the technical design of this software.
The Erase button lets you "Zero Out All Data", but data to me is a file (whether or not it is readable in the directory of not). Whereas Free Space can be either virgin territory or trashed files with the directory info stripped clean. So why do you say that Zero Out All Data would include virgin disk space when there was never data there ?
Also if Erase>Zero Out All Data "writes zeroes to every byte on the drive", and projects an erase time of 13 hours, then why does it estimate 2 days 9 hours when I choose Erase Free Space>Zero Out Deleted Files? (Which further confuses the reader with this Apple description: It writes zeroes over the UNUSED space in the disk.) (My capitalization for emphasis). Yes, parts of it are CURRENTLY not being recognized, but it IS filled with data (as opposed to the virgin space being filled with no data).
So you can see why I am confused.
And though you may be right, I alwatys ask. "Would you bet your child's or your mother's life on your answer?"
That's why I left it an Open question for the moment ... hoping to also snag an Apple Moderator.
Thank you for your help though.

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No Erase option in Disk Utility for an SSD Drive!

Hi guys,
Made a time machine copy on a 500gb external hard drive of my 13" MBP with a HDD currently in it.
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Opened up 13" MBP in restore mode. Chose restore from time machine back up.
Choose the time machine external drive as source. Then chose the SSD drive to restore to.
Said it was erasing the drive... Asked for a password...
I typed in my usual password. It then said the SSD drive couldn't be erased.
Took the SSD out and put the original HDD back in.
Plugged the SSD into a firewire 800 caddy to try erase it in disk utility as an external.
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Chris

Aha! I only looked at 'format' list, didn't notice the 'option' list.
problem solved.
thank you !

Brand new Mac, had to erase drive through disk utility as time machine back up failed. Now disk utility only has the option to install Mountain Lion which my Mac won't allow. Anyone any ideas as my Mac won't load anything up but disc utility!

Brand new Mac, had to erase drive through disk utility as time machine back up failed on initial setup, USB cable popped out Now can only access disk utility as won't load to log in screen. The only has the option in disc utility is to re-install Mountain Lion which my Mac won't allow or loading another time machine back up but after an hour of it processing, that didn't resolve the issue either! The time machine back up is the latest back up of my Mac Book Pro which was using OS X Maverix. I'm guessing I'm going to have to take my Mac to the store but that would be a hassle so does anyone have any ideas?

Follow this guide using another Mac.
Insert your newly created Mavericks USB into you Mac, press the power button and then hold down 'option,' until it gives you an option to boot from the USB. You will then be able to erase the internal disk with Disk Utility and reinstall Mavericks straight after.
After that you should be able to use Migration Assistant to restore your applications and user data.

Erase functions on Disk Utility in Lion

Having installed Lion on my MacBook Air I find the erase functions on Disk Utility are no longer available. Any ideas?

Michael Superczynski wrote:
http://support.apple.com/kb/ht1533
Thank you for the link Michael.
I'm still wondering why I can't erase or partition my disk.
It works fine in SL on my MacBook Pro Unibody (late 2008). It even works on my old white MacBook from 2005 which I upgraded to the OS X Lion.

Why can't I erase HD with Disk Utility?

I have a MBAir 11" with Mavericks. I want to erase the HD. I go to Disk Utlity>choose Macintosh HD>Erase. All choices are greyed-out (Format, Name, Erase Free Space, Security Options, Erase). I can't choose anything. What am I missing?

Hi Loner T,
Here is what I get.
I'll also put a picture up of what I'm seeing in disk utility...
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        *500.1 GB   disk0
   1:                        EFI EFI                     209.7 MB   disk0s1
   2:          Apple_CoreStorage                         499.2 GB   disk0s2
   3:                 Apple_Boot Recovery HD             650.0 MB   disk0s3
/dev/disk1
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:                  Apple_HFS Untitled               *498.9 GB   disk1
                                 Logical Volume on disk0s2
                                 4306F405-E4CD-46A4-A31E-7D7BC1199F32
                                 Unencrypted
/dev/disk2
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        *500.1 GB   disk2
   1:                        EFI EFI                     209.7 MB   disk2s1
   2:          Apple_CoreStorage                         499.1 GB   disk2s2
   3:                 Apple_Boot Recovery HD             784.2 MB   disk2s3
Chris-Prendergasts-MacBook-Pro:~ chrisprendergast$

Cannot write or delete files from DVD+RW after erasing it through Disk Utility. Help.

Hello. I erased (completely not quickly) my 4.7 GB DVD+RW with the help of Disk Utility in which it was successful, it asked me to open Finder, DVD Player or Disk Utility, I chose Finder. Then I dragged a MP4 and burned it, it asked me to name the blank DVD+RW so I named it and then it successfully burned the file onto the DVD+RW, now when I try to burn a file again (as it is a RW) by dragging the file to the DVD+RW window the cursor shows a stop sign with it (the sign which is a circle and there is a diagonal line it it) and it denies to write files again, when I try to remove a file it doesn't do it as well. Please help.
P.S When I secondary click on the DVD+RW icon and click get info it says "Capacity : 4.7 GB" and "Available : 0 Bytes" even when the MP4 file is just 8.3 MB.
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Please Help.

Hello Aditya's Apple,
Thanks for using Apple Support Communities.
If you want to write again to a CD RW or DVD RW disc you will need to first erase it, and then start another burn process. The only time you can burn multiple times to a disc without first deleting what is on it, is by multisession burning. The following article explains more.
Disk Utility 12.x: Record on a recordable CD more than once
http://support.apple.com/kb/PH5823
Disk Utility 12.x: Erase a disk, CD, or DVD
http://support.apple.com/kb/PH5849
Take care,
Alex H.

10.5.2, Screensaver Security, and Disk Utility

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Under Leopard, Disk Utility's repair permissions routine presents a funny user interface. At the outset of the repair process, it ain't exactly clear that anything is really happening even though the repairs are indeed underway.
First thing DU does when the repair process starts is show you a blue progress bar and words to the effect that the process will require about 1 minute more. Then that blue bar sits there doing nothing whatsoever in terms of measuring progress - until about five minutes have passed. During this 5 minute hiatus, DU is building its own permissions data base which it will subsequently use to do its repair work.
Once the permissions data base is constructed, DU's progress bar will suddenly come alive again to show about fifteen minutes longer to complete the repair process. That fifteen minute item changes rapidly from then on, with all repairs being completed in just about five minutes more. (DU took altogether about ten minutes to do its repair thing under Leopard on my computer.)
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Okay, just a little update.
I added the replica server to the "Authentication" search in the Directory Utility, right after the OD Master.
I have also added it to the search path in the Workgroup Manager on my 10.4.11 server, and authenticated. Sees it just fine.
Now, when I fake a failure of the Master, (IE, shut it down), it just hangs forever, and doesn't timeout and move on to the replica.
Am I missing something? Isn't this the point of a replica?
Help?
Thanks!

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"Your Startup Disk is almost Full,
you need to make more space available
on your startup disk by deleting files."
This occurs about 90% of the way through the process (based on where the blue bar is at the time) during the "Creating Temporary File" portion of the process. I know from past experience that I will remain in this portion of the process forever unless I press the "Skip" button to complete the process.
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1. What is the startup disk and why is it full?
2. What should I do about the Your Startup Disk is Almost Full warning?
3. Is my computer actually talking about "regular" disk space (I currently have about 9GB of 80GB free but have seen this warning with 30GB available as well).
4. When I press "Skip" and the blue bar continues to complete the process, have I actually erased free space?
PBG4 15" 80GB HD 1GB RAM Mac OS X (10.4)

The Disk Utility does the erase by creating large temporary files, writing to them, then deleting them. While doing this, OSX may notice the lack of free space on the disk. This is normal, but could cause problems if you are also running some applications that want some disk space. If you let if finish, it should delete the temporary files and free the disk space.
I prefer to run the Disk Utility from the Tiger install disk when doing a Verify, Repair, or Erase Free Space on my boot disk, so I know I won't be interfering with anything running.

Erase button on Disk Utility doesn't work

II'm trying to erase my external HDD so I can use it to restore a backup of my HDD , since there's a problem with my HDD and my MacBook Pro is stuck on startup, but the erase button (is not grey, it looks functional) doesn't respond. I press it and nothing happens. What can I do? I need to backup my files ASAP

Connect the external drive to another mac ( a friend maybe?) and re-format it using that.
I'm not 100% clear on what you're trying to achieve here, but it sounds like your MacBook HDD is corrupted. Make sure you've tried repairing the HDD using disk utility in the recovery partition. This will tell you if the disk is usable. It may repair it and return your system to normal operation.
If your HDD is corrupted or damaged you may have trouble backing it up to the external drive anyway.
Personally I would remove the HDD, replace it with a new one and re-install OS X onto it. While you're out getting a new HDD, pick up a SATA to USB drive caddy that will allow you to connect the old HDD to your new restored Mac via USB. If it's readable then you should be able to copy data off it.
Your ability to re-install to a new hard drive will tell you if the problem was with the old HDD or with the Macbook itself.
If the old HDD is not readable you may have lost your data, or you may need to go to a professional data recovery service. This is why backups are essential. I would recommend using your external drive for backups with Time Machine.

Erase HD in disk utility is grey, not mounted, locked. help!

i have a 2011 mac mini running Mt. Lion. it's running really slowly and i want to wipe the HD and restore it back to orginal factory settings. like the day i brought it home. i boot in to the disk utility using command-R on start up, select disk utility but my mac HD is grey, erase is grey. i can verify it and repair, but cant erase it. when i click "get info" it shows it as not mounted and locked. where do i go from here to restore my mini!
thanks!.

i thought if you booted in recovery mode then you were booted from the partitioned part of your HD, and thus can errase all your data on the HD.
how else does someone restore to factory settings then?

Erasing Volumes using Disk Utility

I used Disk Utility to make copies of numerous cds and dvds. Doing this created a long list of volumes on my harddrive that I can not delete using erase or erase empty space (these fields are grayed out). I tried booting from the OSX disc however when I did that the volumes weren't even visibile. I also tried converting the disk images to a writeable format. All this did was make a copy of the existing volume. Does anyone know how to delete Volumes in another way, either using disk utiltiy or other software?
Thanks,
Dean
Macbook Mac OS X (10.4.7) disk utility, delete or erase volumes

If you are getting nothing for file system what has gone wrong is something in your computer/operating system, not on the iPod.
Try running Scandisk first, then formatting or, at this is not recommended generally, if that doesn't work partition the iPod and then format it.
But you might also want to consider a reload of XP. I reiterate, if it gave you nothing to select under file system this is most likely a problem with your operating system or USB chain.

Erasing ipod with disk utility is it worth a shot?

My 2G ipod is frozen once again can't get it to mount or show up. just asks if I want to ignore or erase the disk or eject. Have tried all the usual tests and self diagnostics. Even tried the tapping on the right side. I'm running the HDD scan now. Just before this happened when it was still mounting I tried to reset and restore it but got a error and failure several times something about the disk . Has anyone had results with erasing the ipod disk with disk utility and then trying to restore and update.? I went to the apple store and they basically said time for a new ipod . It's well out of warranty but I figure its still worth a try erasing if disk utility might help. I already replaced the HD last year and just got a high output Newer battery for it last week so I don't want to give up yet.
Craig
15 TiBook 1GHZ, I.25 dual G4 MDD,10G ipod Mac OS X (10.3.9)

Erasing seems to hang from the beginning in Disk utilty. I tried zeroing all data which takes longer but I've gotten disk utilty to get the progress bar to go about three quarters of the way and then it hangs. I also checked it with techtool pro and it was finding a lot of bad blocks in the scan.
One time I got ipod updater to say it was restored but it wasn't really and I couldn't get the software updated. So I'm back at square one with trying erase with disk utilty but after more than a dozen attempts I'm beginning to think this is a lost cause for resurrecting this ipod HD . This is of course after I received a new extended battery for it last week made by Newer which is only good for 1G and 2G ipods.
frustrated, Craig

HT1782 My usb pendrive was 16gb , but when i erased it through disk utility , its total space is now showing just 2 gb . What can i do to restore the remaining space

pls help me

There was some max size for fat16. 2gig max seems familiar to me.
Log in disk utility. It should tell you what the size of the 'drive' is.
The terminal application will give detailed information that you can copy & paste to this thread.
Macintosh-HD -> Applications -> Utilities -> Terminal
mac $ diskutil list
... clipped ...
/dev/disk2
   #:                   type name               size      identifier
   0: FDisk_partition_scheme                    *3.8 GB   disk2
   1:              Apple_HFS Recover            3.8 GB    disk2s1
wait for the $ then type diskutil list then press enter.
in my case, I have a '4gig' flash drive listed. 3.8gb is close enough to 4.gig.
mac $ df
Filesystem              512-blocks      Used     Avail Capacity Mounted on
/dev/disk1s16            569927296 135962488 433452808    24%    /
devfs                          225       225         0   100%    /dev
fdesc                            2         2         0   100%    /dev
<volfs>                       1024      1024         0   100%    /.vol
/dev/disk2s1               7913360   5744608   2168752    73%    /Volumes/Recover
... clipped ...
another view of my 4gig flash drive is /dev/disk2s1
Post the results fo diskutil list & df here. Thanks.
Try disk utility again. Try formatting again. Did you create multiple partitions?
Be sure to partition the correct dirve. See what disk utility says about the size.
What version of Mac OS are you running?
Robert
Robert

Disk Utility: Disk Scrubbing ("Erase Free Space")

Hi,
I've logged in case 113969827 the following observation:
In a Macbook 10.5.6 using Disk Utility to Erase Free Space
(Disk Utility / Erase / Erase Free Space) with 7-Pass or 35-Pass
Erase on a / partition with 113GB free of 200GB of a 232GB drive
which is Boot Camp partitioned, the other 32GB going to a
flawlessly-running Windows XP, rarely used, the following
issue happens...
The free space (87gb) goes to 0gb.
Has anyone else seen this?
Thanks.
Message was edited by: cracraft

Hey,
Talked with Apple in Texas, Indiana and Silicon Valley on this one
as well Josh...
The bottom line executed so far is:
Shutdown Mac OS X
mount -uw
/usr/sbin/fsck -fy
shutdown -r now
Finder
Disk Utility
Erase / Erase Freespace
Select least secure option and run
Wait until Disk Utility is final (no timing messages)
The above completed okay and your advice to "wait it out"
was right on the ball.
Next, I need to do Erase / Erase Freespace 7-Pass overnight
and then a 35-Pass tomorrow.
The reason I want to do all this heavy "assurance" of deleting
is that if I am required to send this notebook back for the cpu
fan issue, then I certainly want privacy for my disk. But on second
thought, upon receipt, I could just go to the local Apple store and
swap out the disk from one and place it in the new frame and
bootup, retaining my data.
Anyway, thanks for your input today as well as Richard in Indiana,
Matt in Texas, Matt in Silicon Valley.
(There were no errors in the fsck btw though it did say the FS was
modified... odd.)
Stuart
P.S. One would want to do more than the drag-and-drop to the Trash
with Empty Trash btw. I don't think those are assured from undelete
by savvy wizards or other operatives... whereas, 35-pass certainly is
completely secure, assuming the implementation at Apple doesn't
have a backdoor of some kind...
I'll keep this thread updated after the 7-pass / 35-pass which I am
sure just requires extra patience, as you indicated. Thanks!

Disk Utility: Differences between "Zero Out Data" and "7-Pass Erase"?

I'm wondering if anyone knows if there's a significant difference between the "Zero Out Data" erase option in Disk Utility (specifically Disk Utility 10.5.5), and the "7-Pass Erase" and "35-Pass Erase" options in same software.
Here's why I'm asking: I have a co-worker with an iMac G5 20" 1.8GHz with 160GB internal hard drive. As a result of the power supply overheating a week ago due to dust, some hard drive problems resulted. I'm trying to assess whether these are 'soft' formatting problems that can be recovered from, or 'hard' problems requiring replacement of the hard drive and/or power supply.
Following the failure, I removed the dust and restored the iMac to servicable form. The power supply seems to be OK now. The next thing was to attempt to recover as much data as possible from the 160GB, as the last full backup was a week old. Carbon Copy Cloner, shell copy via 'sudo cp -p -R -v', Finder copy, and DiskWarrior recovery all met with problems. TechTool Pro identified a huge swatch of unreadable sectors during repeated surface scans. Unfortunately, these unreadable sectors were located midway in the OSX boot partition (an 80GB partition), and not in the other 80GB partition devoted to lower priority video data.
When I was satisfied I had backed up the data to the best of my abilities, I next set out to reformat the drive and see if the bad sectors could be eliminated or remapped out of existence. I did a "Zero Out Data" erasure in Disk Utility (with no errors during the erase), but TechTool Pro showed the bad sectors persisted in equal strength at the same location. I next executed a sixteen hour "7-Pass Erase" (again no errors, and confirming that it takes about an hour per 10GB). The next day when I ran TechTool pro, all of the sector errors had disappeared. I'm a bit perplexed as to why the "7-Pass Erase" seems to have recovered the use of the drive. Is it possible that there are simply thousands of bad sectors now remapped that I'm not seeing? [If so, how do I check for this?] TechTool Pro has not reported any S.M.A.R.T. issues to date on the drive. What am I to make of that?
There are some related threads I've checked into, but I'm not sure how to properly assess my situation based on this information:
<http://discussions.apple.com/thread.jspa?threadID=232007>
<http://discussions.apple.com/thread.jspa?threadID=138559>
<http://discussions.apple.com/thread.jspa?threadID=118455>
Since the iMac has three weeks left on it's one year warranty, and I've already moved the user to another machine temporarily, I'm thinking that the smart thing to so is to send it in to Apple to have them look at the power supply and hard drive. That way, when it returns, even if there is still a lingering hardware problem, at least it will be covered under warranty for another 90 days.
Any thoughts?
iMac G5 20" 1.8GHz Mac OS X (10.4.6) 1.25GB RAM, 160GB hard disk, SuperDrive

HI, Bret.
The only differences between "Zero Out Data", "7-Pass Erase", and "35-Pass Erase" are the number of times a binary zero is written to every bit on the disk. "Zero Out Data" writes a binary zero once, whereas the 7- and 35-Pass options write a zero seven and 35 times, respectively.
Technically, one pass with Zero Out Data should be sufficient to map bad sectors out of service, a process also known as sparing. If a bad sector is encountered, it is both marked as "in use" in the directory's allocation table and added to the directory's "bad blocks file."
My understanding is that the Surface Scan of Tech Tool Pro should identify bad sectors every time it is run unless the bad sectors have been locked out by the drive controller of the ATA drive itself. This is because Surface Scan checks the entire surface of the disk.
What may have happened is that running "Zero Out Data" spared the bad blocks from a directory standpoint, but did not result in the drive's controller locking out those sectors for reasons detailed in the "Surface Scan" section of the Tech Tool Pro manual. However, the 7-Pass Erase may have resulted in the drive's controller locking out the bad sectors and why Surface Scan did not pick them up after such.
Given the problems you described, I concur with your plan to have Apple check the affected computer. You might also want to consider purchasing an AppleCare Protection Plan for that Mac: I recommend and buy these for all my Macs.
For some additional information on bad sectors, see the "Bad Sectors" section of my "Resolving Disk, Permission, and Cache Corruption" FAQ.
Good luck!
Dr. Smoke
Author: Troubleshooting Mac® OS X
Note: The information provided in the link(s) above is freely available. However, because I own The X Lab™, a commercial Web site to which some of these links point, the Apple Discussions Terms of Use require I include the following disclosure statement with this post:
I may receive some form of compensation, financial or otherwise, from my recommendation or link.

Erasing Securely in Disk Utility

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