Is "Zero" Out Safe Enough?

I need to erase the HD on my MacBook Core 2 Duo.
I have sold it on Ebay and was wondering if the "zero out" option in Disk Utility is safe enough for when I pass my laptop on to it's new owner.
Is it okay if I don't do the 7-time pass erase?
I honestly don't have the time to wait hours...I have to get it packed up and shipped.
What do you think? Will my hard drive be secure enough?
Thanks!

It all depends on how sensitive that data is. The chances of that data on a zeroed-out hard drive can be recovered are close to nil. But the chances are not actually nil.
For a quick & dirty solution, ensure all your sensitive files are in your home folder. Then turn on FileVault. Choose the "secure erase" option when turning it on to ensure that the moved files are completely wiped out. Choose a very strong password; something like dUcr5Faw2uG2cubr.
Them just do a quick erase and reformat, with no zeroing out. Reinstall the OS. The next owner might easily be able to recover parts of the System, Applications, etc., but your data will be completely gone.

Similar Messages

How do I properly zero out or erase the hard drives in my early 2009 Mac Pro 4,1 tower?

How do I properly zero out or erase the hard drives in my early 2009 Mac Pro 4,1 tower?
I assume there are already instructions on Apple.com someplace but haven't seen them yet… I have to one terabyte drives one the operating system the other is blank I want to start fresh I want to zero out both drives but I didn't want to make any mistakes
I know I can use disk utility to 0 Out Dr., #2 that means I will have to take out the operating system hard drive out of my 2008 Mac Pro and put it into my 2009 Mac Pro to use the disk utility to zero out drive one the OS drive in my 2009 Mac Pro am my correct
I just need a little bit a help I want to go slow so I don't make any mistakes with the sleds or with the erasing process which journaled to choose encrypted or not etc. etc.
Furthermore is there instructions on the site on how to change the hard drive into a different sled because the sleds and my 2009 are different than my 2008 any advice
Thank you

I'm doing this because my friend told me that zeroing out the drive can nap bad sectors and also later for some kind of diagnostics usage of the drive or something like that he wasn't really clear
My friend was really specific he said choose the option that writes zero's once over the drive that is plenty good enough I was inclined to use the maximum seven write ...I just want to make sure the drive has no bad sectors and that's it's it's zeroed out for possible future diagnostics usage or something that he said was usable later
he also advised me to run a test on it but I don't have the software you mentioned or the software that he has… So I may have to take the drives over to his house unless you have some kind of free software that's easy to use that you could suggest that will not only zero out the drive but test the drive completely
I am completely new to Mac I'm no dummy but at the same time I'm not super technically capable I mean I can surprise myself I'm pretty good but I need a good teacher… How expensive is this lifeguard software?
Thank you

Question about zeroing out data...

I'm currently zeroing out my Time Capsule's hard drive and starting fresh with backing up. I started doing a 7 pass method the other day, but figured it was overkill and bad on the hard drive, so I stopped it a quarter of the way through pass 2. Does this mean that at least the one full pass was done successfully? Also, to make sure that everything is truly zeroed out, I started a one-time zero out erase. So, does this mean, then, that my TC truly has been zeroed out twice for starting over on my backups?
And, while we're on the subject, I did some research on zeroing out data. Most people are in agreement that doing one pass is good enough. Apple recommends twice for a fully secure wipe. While researching this, I found that some claim that zeroing out a hard drive during a 7 pass and 35 pass method significantly decreases the lifespan of a hard drive. Is this myth busted or confirmed? Also, is zeroing out data only once already harmful to an HD's lifespan?

William Boyd, Jr. wrote:
apple_kmj wrote:
I'm currently zeroing out my Time Capsule's hard drive and starting fresh with backing up.
I'll leave to others the answering of your questions, but I have one of my own: What are you hoping to accomplish by zeroing out your Time Capsule's drive? I would only consider that useful if I were planning to sell or otherwise dispose of a Time Capsule.
I heard that it's the best way to go if you have a lot of data synced and you don't want to individually pick out data to delete. Also, backups were taking a while, and I noticed that my Time Machine had nothing on it even though my Time Capsule showed as having almost 80 GB of data backed up. So, just to eliminate any potential problems, I zeroed out data and started over again.

Recommended # of "zero out" passes to securely erase hard drive?

I'm selling some old hard drives. Apple's Disk Utility (OS X 10.4.8) provides the ability to "zero out" the data on a hard drive. Options include ability to run 1, 7 or 35 zero out passes. The 7 option will take a day per drive, and the 35, obviously, several days.
Is 1 zero out pass good enough to securely wipe the data? Is running two consecutive 1 zero out passes twice as good as one pass?
thanks!

Depends on how paranoid you really are, how important it is that no data be recoverable, and who might attempt to recover data from the drive.
In most common cases one pass should be sufficient. If you have extremely top secret NSA data on the drive that highly trained spies will attempt to discover and have access to the most sophisticated data recovery equipment, then go for 35 passes.
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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.

Zero Out Data on a SSD drive: Are my findings correct?

"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."
http://support.apple.com/kb/HT3680
Seems to hard to believe, as I've seen some of the top participants here clearly say that first your set a new partition, then erase Macintosh HD, then zero out data?

Retired Engineer, do you have any references? What I have read says otherwise.
Drive Wear & Tear
What is your estimation of wear and tear on the flash by writing to 0's. What percentage of the drives total usage has been "wasted"? I thought even consumer drives where capable of 1000 - 10000 rewrites per cell, whereas enterprise SSDs are capable of over 100,000: http://www.computerworld.com/s/article/9112065/Solid_state_disk_lackluster_for_l aptops_PCs?taxonomyId=19&pageNumber=1&taxonomyName=Storage.
"For one thing, it matters whether the SSD drive uses SLC or MLC memory. SLC generally endures up to 100,000 write cycles or writes per cell, while MLC can endure anywhere from 1,000 to 10,000 writes before it begins to fail, according to Fujitsu's Hagberg. For its part, Western Digital's laptop hard-disk drive boasts up to 600,000 write cycles."
That's an old artcile too. Slightly newer, in late 2008 Micron/Sun achieved SLC NAND chips capable of over 1,000,000 write cycles: http://investors.micron.com/releasedetail.cfm?ReleaseID=440650 . I imagine things have gotten slightly better in the last 4 years.
Data Wiping
This paper (http://static.usenix.org/events/fast11/tech/full_papers/Wei.pdf) states, "In most cases, overwriting the entire disk twice was sufﬁcient to sanitize the disk, regardless of the previous state of the drive."
Going on however, "Overall, the results for overwriting are poor: while overwriting appears to be effective in some cases across a wide range of drives, it is clearly not universally reliable. It seems unlikely that an individual or organization expending the effort to sanitize a device would be satisﬁed with this level of performance."
The best method I have found for wiping an SSD on a Mac is the (SAFE) Scramble and Finally Erase process as described in this UC San Diego research paper: http://cseweb.ucsd.edu/users/swanson/papers/TR-cs2011-0963-Safe.pdf.
According to their paper, the effectiveness of the procedure is equiavlent to degaussing a magentic drive. Another tidbit, the SAFE technique is replicated by Sandforce controller when someone reformats the drive (as mentioned by Linc Davis above, however, I believe this is specific only to Sandforce controllers).
References:
http://www.schneier.com/blog/archives/2011/03/erasing_data_fr.html
http://www.computerworld.com/s/article/9211519/Can_data_stored_on_an_SSD_be_secu red_
http://arstechnica.com/security/2011/03/ask-ars-how-can-i-safely-erase-the-data- from-my-ssd-drive/
http://static.usenix.org/events/fast11/tech/full_papers/Wei.pdf
http://cseweb.ucsd.edu/users/swanson/papers/TR-cs2011-0963-Safe.pdf

If I never turned on Time Machine and later zeroed out my HD can anything be recovered, ever?

I recently sold my Macbook Pro and I'm wondering if files can be recovered evern after I zeroed out my HD? I did a one pass zero out because I read that one pass is good enough, but I'm a bit concerned that Time Machine will be able to recover files.

Are you talking about the local snapshots that Time Machine uses on an internal drive or did you sell an external drive that you were using with Time Machine?
In any event, it's unlikely that any normal person could recover any data - only a real forensics data team would be able to do it, I would think (and, even then, it's unlikely that they could get much).
Don't worry - I doubt that a buyer would be willing to spend thousands of dollars to attempt to get to your data.
Clinton

Zero out GL balances

The assets were not working in current system because depreciation was not run for past few years. we are loading assets all over again. since the assets were not working, the postings were made to depreciation expense account as journal entries. similarly postings were made to the apc and accumulated depreciationa ccount through FB50. now when we load the asset balances in AS91, they will duplicate as they already got balances in apoc account and dpereciation account (that are non recon accounts), so we will have to zero out the balances in these accounts. also will have to zero out balances in depreciation expense account since they already posted to this account for the whole year of 2009, they willneed to be zeroed out till their go live date which is somewhere in august.
How do we zero out the accounts. DO we create conversion accounts for zeroing out these balances in addition to the conversiona ccount already created to load GL balances. Or can we use the same conversion account that we created for GL. Is there any other way to zero them out?

You can use the same conversion account that is created for GL or create a diff account , it shoudn't really matter either of the cases would work
but why do you want to keep 2 dioff conversion accounts for zeroing the balances , accordign to me one should be enough.

When the Apple Store tests a zeroed out hard drive, is their test as intensive as wd lifesaver etc. software's in napping out bad sectors etc.

When the Apple Store tests a zeroed out hard drive, is their test as intensive as wd lifesaver etc. software's in napping out bad sectors etc.
I do know one test at the Apple store is a three or four hour test that is very thorough for the whole Mac Pro computer, system by system test, I'm curious what kind of test they perform if you're testing the hard drive for bad sectors or whatever I'm a novice
I mean is it as effective or more effective than the software called wd lifesaver?
Does anyone have any idea what software they use or is their test only testing the systems of the computer and not just the hard drive?
I am moving from PC to Mac right now I have not even use my 2009 Mac Pro yet I was told to have the hard drives zeroed out and tested to start with a clean slate this is what I'm trying to do.
Thank you

The chip on the hard drive itself basically takes care of bad sectors. If an operation tries to write to such a sector, the drive will mark it bad and move onto the next one. That's why zeroing the drive effectively does the operation of mapping bad sectors - the whole drive is checked.
Their general hardware test does not do a full drive check, as far as I remember - the memory check can take a long time, though, since they're looking for random errors.
So for your Mac Pro, you should feel confident that doing a one-pass zero (don't do more than one pass, it's a waste of it me), will be enough initialization for the drive. And many drive experts don't even bother with that, relying on modern drive chips/firmware to do the job of checking for bad sectors on the fly.
Matt

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.

Hard Drive problems / unable to Zero out Data etc.

Hallo.
Here is the problem: I have several WD Raptor Hard drives 74 GB working without problems. One of them is my system drive , others are used as Sample libraries HD or HD for recorded audio (I have Firmtek SATA card so I can use more SATA disks...). This summer I bougt new WD Raptor ADFD 150 GB drive to expand my storage for Audio Data... But I encountered a few problems like when I tried to copy a folder from this HD to another and this folder was quite big (15 GB or more) , it never get copied completly and the copiyng freezed in the middle or alike. So I had to move subfolders of this "big" folder manually... Also when I backupped Data from this drive to another with Apple Backup 3 it SOMETIMES did not backup and freezed. This happened in case of creating new backup file to new location, not when backupped to location with already existing backup file.
I tested the drive with the OSX Disk Utility (Verify Disk) and it said it was OK. Than I tested it with Tech Tool Pro 4 (Surface Scan) and it found a few ( two, sometimes three) bad sectors. Sometimes TecToolPro also freezed and I had to Force Quit it or shut down my Mac by pressing the Power button. So I moved the data away from this disk and tried to Erase it (Zero Out Data) with Disk Utility. Disk Utility started and reported that it will take 27 minutes. But after a few minutes it freezed and did not finish eerasingúzeroing the disk (I let it for whole night...). And Disk utility freezed so I had to Force Quit it. I tried it many times without success. Disk utility only could Erase it or create new partition but never Zero Out Data. Than I tried to Zero Out this disk in SoftRaid utility (even this disk was not in SoftRAID or any RAID setup) and it worked. But after I Scanned it's surface in Tech Tool Pro again, it found the bad sectors again...
So I took the disk to my computer dealer and he gave me new one - the same WD Raptor ADFD 150 model. I installed it (in lower bay inside my G5) , initialized in Disk Utility and than I did run the Surface Scan test in Tech Tool Pro. I could see the number of block that were tested increase for a while but than it stopped for a few minutes (10 or more ) and after a while it reported that it found 39 bad sectors! Wow! Fresh new Hard Drive! So again I tried the whole process: to Zero Out this new disk in Disk Utility and Disk Utility freezed. But SoftRaid utility Zeroed this disk successfully - but than after this procedure TechToolPro reported that 1 bad sector was found... I need to say that the Surface Scan test in Tech Tool Pro never got finished (only once when I let it work for about 6 hours) as it reported about bad block(s) after a few minutes or it freezed after a few minutes...
SO I took this new disk and installed it to a PC I have and I tested it with Western Digital Datalifeguard diagnostic utility (from Floppy disk). All tests were fine. It also wrote Zeroes to whole disk without problems. Fine. I reinstalled the disk back to my Mac and even before I initialized it in Disk Utility I tried to Scan it's Surface in Tech tool Pro. After a fef minutes it probably freezed , as it is scanning Block 19744512 for ever now - and it found three bad sectors already...
So what do you think about my situation? Shall I trust the Western Digital diagnostic utility (but on a PC) or should I visit my dealer again?
PS-I have Tech Tool Pro 4.1.2
Message was edited by: Diamond Dog

Something to try:
Open Disk Utility (Applications > Disk Utility)
Select your external HD on the left side of the Disk Utility window
Check the partition map scheme, near the bottom of the Disk Utility window
If it is not GUID (assuming you have an Intel iMac), consider repartitioning your HD to GUID. The Windows partition scheme on many external HDs. FAT 32, often has problems accepting large data transfers from Mac-partitioned hard drives.

Can I do a clean install of Lion, onto my Mac Book Pro4,1, that is currently running 10.5.8? I have seen U-tube videos on how to do a clean install to Snow Leopard, and another from SL to Lion, but can zero out my HD, and do a clean install to Lion?

Can I do a clean install of Lion, onto my Mac Book Pro4,1, that is currently running 10.5.8? I have seen U-tube videos on how to do a clean install to Snow Leopard, and another from SL to Lion, but can zero out my HD, and do a clean install to Lion?

See this article.

How can I zero out offset voltage at the start of the program?

I have a simple program that reads a voltage input and outputs the results to a file. The voltage has an offset (which changes from test to test), and I am interested in zeroing out this value at the start of acquisition. I could use an example of how to do this. Thanks.

Try this simple method...
Right click on the icon which represents the offset voltage. Select create: Invoke Node.
Use the finger pointer and click on the "Method" of the newly created Invoke Node. Choose "Reinit To Dflt"
Place this Invoke Node at the beginning of your vi by running the Error In through it.
And "voila"... everytime you run your vi, it will reinitialize it to the default value... which can be zero.
You can use the same trick to re-initialize values if a certain condition is met within your vi.
-have fun-
JLV

Need help to install & use iErase app to zero out iPhone after restoring/erasing

I plan on buying a ew iPhone5 and trading in my iPhone 3GS. After doing much research on the topic, I've learned that the best way to ensure that no one can find personal data on my old phone is to restore it to the factory settings thus "erasing" all of my data and then to install and run the iErase app that will zero out the hard drive. I bought iErase on itunes and t's on my computer. I restored my old iphone (erasing all my purchased apps including iErase) but when I connect it to my computer to reinstall the iErase app, it syncs and reinstalls all of my personal settings, data, etc.. Am I missing a step? After restoring my phone, it seems that I might have to go into itunes on the phone and repurchase iErase ($6.99). The app iis designed to zero out the free space on the phone and will not touch whatever is installed. Thus I will have to enter my itunes password etc. which won't get zeroed out. I suppose I can just change that later. Any suggestions?
Thanks

What's a DFU mode restore?
Also, I read the reviews as well as others on different sites and it seems that some people aren't using the app correctly. It only zeros out free space on the phone. Many seem to think that it will delete everything on the phone. That's incorrect. If you install and run it without restoring or ersaing your phone first, it will look like nothing happened. All of your info, apps and personal data will still be there. You have to delete all that stuff first (thus designating it as free space) and then run ierase to zero out the deleted info. At least, that's my understanding of how it works.

Help Zeroing Out Data On eMac

I'm trying to wipe out the hard drive on my folks' old eMac. I'm going to recycle the computer but it is important that I at least zero out the data and not just erase it superficially. The disk that came with the mac is 10.1.4, so I gues it doesn't have a Zero data option when I try to start fromt the disk. Sadly my old firewire cable is MIA and I'd rather not have to buy another one just for this.
Is there another way to zero the data?
More info:
I can start up from the install disk that came with the machine (holding the C button while powering up) which gets you to an install page. I've selected Disk Utility from the menu bar and from there I can get to the "Erase" tab. At this point with later systems I guess you would select an HD and there will be an "Options" button that lets you choose "Zero All Data", etc. But I can't find such an option on the older disk.
The eMac was running 10.3 something after updates. However, at this point I have superficially erased the data, as I was hoping that clicking on "erase" would give me further options. It didn't. So i's not 10.3 anymore, and I have not yet entered any info for a new user on the computer.
I also have the 4 recovery disks that came with the eMac, if those matter.
Help appreciated,
Max

Well I bought the bullet and ordered a new 6 pin 9 pin firewire. Which, with the internet, is actually not much of a bullet these days. I don't imagine I'll use the cable for that many other things, but that's okay. I had heard about the gibberish-file-copy method, but I think this'll be easier. Thanks tho.

Is "Zero" Out Safe Enough?

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