Erase Free Space Feature

[Ormond]

Hello again,

I'm experimenting with the erase free space feature of Disk Utility. As you'll probably recall, this feature writes zeros over any data you've trashed, making it difficult (or maybe impossible) for that data to be recovered.

In case anyone is curious, it took 3 and half hours to do the quickest erase (one pass of zero writing) for an empty one terrabyte drive, on a 2011 iMac.

At the end of the process I received this error:

secure erased failed -
couldn't create temporary file

If anybody has insight in to this, thanks for sharing.

 

[honestone]

I have an older 17" MacBook Pro, and it has the last version of Snow Leopard, OS 10.6.8, on it. Recently, one of my 1 TB Seagate External Drives started giving me issues, in that TechTool Pro kept warning me that the drive was starting to fail. I then decided it need to be replaced (have subsequently done that with a 512 gig Samsung 850 Pro 512 gig SSD), I of course needed to dispose of the drive, so I went ahead and attached the drive to the MacBook Pro, and did ALL levels of the Erase process that Disk Utility offers. The last (and most secure) option, called 35-pass, took over 3 days, but I never got any such error. But, I was erasing the entire contents of the drive, so it is somewhat different.

I just did a google search of "secure erase failed - couldn't create temporary file", and I did not see one single explanation of how to alleviate this error with Disk Utility. I did see, though, a recommendation to use the software CCleaner. It can be obtained for free from Piriform, and here is the link:

http://www.piriform.com/ccleaner-mac

And, some folks did have success with it. This link should also help:

https://www.piriform.com/docs/ccleaner-for-mac/using-ccleaner-for-mac/wiping-free-disk-space

Yes, it is frustrating that an explanation/solution cannot be found. But at least CCleaner seems to be a viable option.

I was reading some more about this issue, and from one of the links, one of the users posted this:

"I was attempting to erase free space on my laptop with mac disk utility and received the error message could not create temporary file and found the free space had been erased. Check about this mac, storage to see if free space was erased."

 

[honestone]

I am having an "obscure" strange issue with CCleaner. It wrecked some havoc with Firefox (not my usual browser) and Google Chrome (my default browser). I am going to do a restore from my SuperDuper! backup that I did on Saturday (only need to save a couple of files before I do), to get things back to what they were.

So, I would not download it, if I were you.

PS: Just finished the Restore from my SuperDuper! backup, and things are fine. I suspect that installing CClean resulted in some possibly "nefarious" stuff being installed. I'm glad I got rid of such garbage!

 

[Spawn_Dooley]

At the end of the process I received this error:
secure erased failed -
couldn't create temporary file

Prior to seeing the error had you followed the following procedure:

• Restart & while the iMac is restarting,
  
• Hold down the Command key and the R key simultaneously.
  
• Hold down until the Apple icon appears, then release both keys.
  
• Four options should appear, choose Disk Utility.
  
• Continue with Erase Free Space procedure as usual.

 

[Ormond]

Hi there Spawn,

The first time I did it I just clicked erase free space in disk utility. That generated the error, so I did a little research and discovered the process you refer to above.

When I did the Command R start it went automatically in to Internet recovery, you know, with the spinning globe. Three hours later the globe was still spinning, and it was nap time for Granda Geezer Hippy, so I powered down out of it.

Perhaps this question will advance the topic. I'd like software that will allow me to see the files that have been deleted (trash emptied). If I could see them before erasure, and compare to after erasure, then I'd know whether the erasure has done it's job. Given that this feature is clearly unreliable, it'd be nice to be able to check it's work.

I'd read a number of posts from users who experienced the same error, and who said the process seemed to have worked in spite of the error. But I don't know how they came to this conclusion, or how to replicate their process.

Many thanks for any advice, and nice to meet ya.

 

[Spawn_Dooley]

What happens if you press Option instead of Command R? Can you navigate to Disc Utility?

 

[Ormond]

Hi Spawn,

I have used the option key boot method, so I know what you're referring to. As I recall, it doesn't show disk utility, but a list of bootable drives. Right? No?

Perhaps this will help. In the experiment described in my opening post I was booted from Yosemite on an external USB disk, and was attempting to secure erase the hard drive built in to my Mac. It may have worked, or maybe not, seems impossible to tell so...

I'm shifting my focus to finding software that will allow me to see the data that becomes invisible once you empty the trash. Given that the data is still there on the drive (until it is overwritten by new data) this can't be that hard, right?

Once I can see the hidden trashed files, then I'll be in a position to know if they have been secure erased, ie. written over with zeros.

Please feel free to comment upon this strategy, as I'm doing all this specifically to learn more about Mac security and related issues.

Thanks!

 

[Ormond]

In case it might be helpful to some future reader....

I found a free app called DiskDrill....

http://www.cleverfiles.com/

... which allows you to see (and maybe recover) files that have been emptied out your OSX trash. Of course this only works if the files in question have not yet been overwritten by new data.

I ran DiskDrill on the drive I secure erased with Disk Utility. It appears that Disk Utility did in fact completely erase that drive, even though it threw up errors at the end of the process. This concurs with a number of other posts I've read on the subject.

 

[Spawn_Dooley]

... which allows you to see (and maybe recover) files that have been emptied out your OSX trash. Of course this only works if the files in question have not yet been overwritten by new data.

To add an important note to this, it only works if Disk Drill has already been monitoring the drive that you wish to recover deleted files from.

 

[Ormond]

Thanks Spawn. Yes, I am very new to DiskDrill, and secure erase too, so nothing I say about any of it should be read as expert testimony.

At this point my interest is limited to just being able to see the hidden files so I know whether or not they are actually gone. If you should know of any reason why I should question DiskDrill when it says there are no files on a drive, I'd be happy to learn from your experience.

 

[honestone]

To add an important not to this, it only works if Disk Drill has already been monitoring the drive that you wish to recover deleted files from.

Good tip, Spawn_Dooley! That's definitely useful information.

 

[Spawn_Dooley]

Good tip, Spawn_Dooley! That's definitely useful information.

Thanks, honestone, Disk Drill remembers all metadata and properties of the deleted files making it possible to restore deleted files with their original file names and location.