How Does 'Permanently Delete' Overwrite Data on a Hard Disk?

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How Does 'Permanently Delete' Overwrite Data on a Hard Disk?

Postby Prof » Tue Aug 31, 2010 1:44 am

What I mean here is:
1) I need to permanently delete stuff from my hard disk due to disk space limitation.
2) But I still want to recover some files that were deleted prior to the current permanent deletion!

Therefore, I would like to know if permanent deletion works the same way as normal deletion - where it, first, overwrites the disk with the old data which is still being recovered.

I know it is not the best or ideal way of doing it but unfortunately I don't have enough space on my current hard disk to fully recover stuff without deleting things.

Therefore, my quick strategy is:
1) To recover stuff first. Save if data is OK or permanently delete if it's rubbish/unrecoverable to free up space before continuing. (Sorry, preview doesn't help to make a decision on what to recover or not. So, recovering first then reviewing...).
2) Then, resume data recovering and recover more stuf... and so on.
...
3) Then start all over from 1) above and repeat procedure until all stuff on disk is recoved.

Now, I will be saving recovered stuff on a different partition(s) from where it's being recoved. Does that help at all?

Basically, when I permenantly delete data from a partition which 'partition' is being overwritten?
a) The current partition where data is being deleted from?
b) The Windows partition under which deletion is taking place?

Thanks.
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Postby M.Mao » Tue Aug 31, 2010 10:09 am

Dear Prof,

Generally, if you overwrite the partition or hard disk (delete original data or format the partition, and then save new data), it's hard to recover lost files as parts of the data may has been overwritten.
For example, you have 10GB data on a partition, and then you delete it and save 5GB new data to this partition, you still have a chance to recover 5GB lost data. But if you save more than 10GB new data to the partition, you probably cannot recover lost data successfully from the partition.

However, if the "permanently delete" you mentioned is "wipe" a partition or hard disk but not save new data on it, we are sorry that the data is lost forever and you cannot recover it.

About your strategy, we think you can do that, and of course you should save the recovered files to the partition or hard disk which does not contain the lost data. Meanwhile, we also suggest you do not install our program on the partition which contains lost data. Otherwise, it may result in overwriting of data, and would result in permanent data loss.

Besides, when you try to save the found data, you can use "Find file by name" and "Search files" to filter the found files, so that you can only save your desired files. You can filter the files by their file name/size/type/date, etc. (for example, you can type '*.jpg' to find all the '.jpg' files through "Search files" function)

At last, in order to help you better, please offer the information below:
1.How did you make the "permanently delete" process? Please tell us more clearly.
2.What is the file type(s) of your lost files?
3.How many partitions did you have? Which is the partition you want to recover data from?
4.Could you tell us the exact version of our product you are using?

Sincerely,
EASEUS Support Team E
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http://www.easeus.com/support.htm
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Postby Prof » Wed Sep 01, 2010 9:01 am

At last, in order to help you better, please offer the information below:

1.How did you make the "permanently delete" process?

I'll use Eraser etc.

1.Please tell us more clearly.

I will recover 'lost' folders/files from a partition.
Save them onto a different partition. Review 'recovered' folders/files.
If OK, leave them there.
If not, permanently delete using Eraser etc.
This is because I will need the space they occupy in order to continue recovering more lost folders/files.

When I finish that partititon, I will move on to another partition ... untill I recover stuff from all partitions on the secondary disk.

2.What is the file type(s) of your lost files?

Oh, various of all sorts.
But mainly, JPEGs, GIFs, PSPs (Paint Shop Pro), some PSD (Photoshop), HTML, PDFs, and common desktop software packages (MS Office, some Lotus Smart).

DRW will only show JPEGs/GIFs and Word/RTF etc.
My stuff is mainly PSPs, (Paint Shop Pro), some PSD (Photoshop), HTML, PDFs etc and MS Office, some Lotus Smart - in that order.

3.How many partitions did you have?

4 on the primary HDD (Win2k Pro, PagingFile, WinXP and an Extended, where lost folders/files will be saved to)
and
6 on a secondary HDD.

Which is the partition you want to recover data from?

Mostly all the partitions, or at least 4/6, on the secondary HDD, Hard Disk1. Most 'lost' stuff are on this secondary HDD, or Hard Disk1.

And found stuff will be saved onto the Extended space on the primary HDD, Hard Disk0.

4.Could you tell us the exact version of our product you are using?

Data Recovery Wizard 5.0.1.

My question, when I delete recovered stuff from the Extended partition space on the primary, but the stuff was originally recovered from a partition on the secondary disk, which partition is now being overwritten, please?
a) The Extended partition, where stuff is being deleted
b) The partition on the secondary disk, where the stuff was originally recovered from.
c) The Windows partition, under which stuff is being deleted. In this case, WinXP.

Thanks.
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Postby M.Mao » Wed Sep 01, 2010 10:33 am

Dear Prof,

Thanks for your detailed information. Now we feel more clearly about your situation.

About your question, if you saved the recovered data to "Extended partition", the original lost data (which you deleted from this partition before) on this partition will be overwritten. If you didn't do anything change on the partition which you want to recover data from, generally the lost data on that partition will not be damaged or overwritten.

But we feel a little strange that why you would like to use Eraser to permanently delete the useless found data? If you find the recovered data is of no use, you can just delete it and empty from recycle bin to free up space.

Besides, our product doesn't support previewing PSP and PSD files indeed. After you recovered these files, you can use proper programs to open them. If you encounter some problems using our product, please let us know.

In addition, could you tell us how you lost data from the secondary HDD?

Sincerely,
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http://www.easeus.com/support.htm
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Postby Prof » Wed Sep 01, 2010 11:43 pm

Thanks for your detailed information.

My pleasure.

About your question, if you saved the recovered data to "Extended partition", the original lost data (which you deleted from this partition before) on this partition will be overwritten.

I saved all usefull stuff from this partition onto another disk which is now disconnect from the PC for a later retrieval etc. So, I'm not worried about original data on this partition being lost/overwritten. In fact, I want to delete permenantly all rubish/useless stuff on this partition to start things from afresh!
Please, see attached a picture file of my HDDs layout.

But we feel a little strange that why you would like to use Eraser to permanently delete the useless found data? If you find the recovered data is of no use, you can just delete it and empty from recycle bin to free up space.

Good idea!
But I wanted to reduce the amount of 'found' or recoverable stuff on all partitions in order to speed up the recovery process. i.e permanently delete all discarded data after recovery so that the DRW program will find 'less' stuff and very 'quickly' since there is less 'lost' stuff on partitions. Does that make any sense? loool. By the way, this why I was previously asking "Which partition is now being overwritten..."

Besides, our product doesn't support previewing PSP and PSD files indeed. After you recovered these files, you can use proper programs to open them.

That's correct. Hence, why I want to save things first, then review them with their appropriate application programs, then delete useless/unimportant data to find space(s) for more stuff to be recovered...

In addition, could you tell us how you lost data from the secondary HDD?

This is a long story... and some time ago...

How my problem started, please, see my posts/EASEUS replies at
http://forum.easeus.com/viewtopic.php?t ... 52dee9d412
This is a long story... and some time ago...

I attached a picture file of my HDDs layout (though I'm not sure whether it was successful or nor as I couldn't 'preview' it).

Thanks.
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Postby Prof » Thu Sep 02, 2010 12:26 am

I attached a picture file of my HDDs layout (though I'm not sure whether it was successful or nor as I couldn't 'preview' it).

Oops, I've just found out that it was due to file 'size limitation' as my original file was 296kB>256KB (max) and far too BIG to view on here!
Attachments
DriveLayout1(Original).jpg
Please note, Drive Layout 1 (Original) 'might' had changed slighly before resizing (Primary). But it was VERY similar if not exactly the same as below.

Partition wise, secondary drive 'Disk 1' has NOT changed much, except, deleting some of its contetnts
DriveLayout1(Original).jpg (83.29 KiB) Viewed 8318 times
DrivesLayout2.jpg
Below is the current drive (Primary) after resizing.

Partition wise, secondary drive 'Disk 1' has NOT changed much, except, deleting some of its contetnts to move data between Disk 0 and Disk 1 while resizing Disk 0 partitions.
DrivesLayout2.jpg (72.54 KiB) Viewed 8319 times
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Postby Maverick » Thu Sep 02, 2010 10:30 am

Dear Prof,

We understand your situation more clearly now. In your case, we think the chance of recovery is small, because the old data has been overwritten when deleted by Eraser and data translation when resizing the partition. But still, we will help you to recover the data as far as possible. We suggest you use "Complete Recovery" module and follow your strategy to perform the data recovery. And please tell us the result. You can refer to this link for more information.
http://www.easeus.com/datarecoverywizar ... -files.htm

If we can be of further assistance, please reply to this message. When replying, please be sure to include this and any other pertinent correspondence in your message.

Sincerely,
EASEUS Support Team V
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http://www.easeus.com/support.htm
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Postby Prof » Fri Sep 03, 2010 5:26 am

In your case, we think the chance of recovery is small, because the old data has been overwritten when deleted by Eraser and data translation when resizing the partition.

I have not used Eraser yet. Infact, I have not installed it at all! But, I downloaded it and I read all about it including screenshots and so on.

I've just run a few, initial 'Complete Recovery' scan by DRW and it finds too much stuff but not my Fashion folder/Files and/or its partition.
And this is why I'm asking what happens if I delete unwanted stuff with Eraser. Will it overwrite onto the partition where stuff is being recovered?

What I did was, I repartitioned and resized my primary disk, Disk 0, from six partitions (C:, E, D, F, G and H) to 4 partitions (C:, D:, E: and G).
Please, see pictures attached.

But still, we will help you to recover the data as far as possible. We suggest you use "Complete Recovery" module and follow your strategy to perform the data recovery.

OK. But I still want to know what happens if I install and use Eraser because DRW finds too much stuff which I don't have space for it to sift through. In addition, I don't really want DRW to find the same unwanted stuff again and again. Hence, why I brought up this issue of using Eraser.

And if I don't use Eraser, but simply delete unwanted stuff after each recovery from a partition, how can I stop DRW recovering from the recycled bin (which probably contains, among other things, the 'unwanted' stuff that I've just discarded). This is a bottleneck problem in terms of a disk space to work on.

But I also moved data around between primary and secondary drives before starting to partition and resizie partitions the primary disk.

Therefore, I may be able to discover some usefull data from the secondary driveart from obviously deleting stuff, overwriting things and son.
Attachments
Primary(Current).jpg
Current Primary disk layout 'after' repartition and partitions resizing (from 6 partitions to 4 now).
Primary(Current).jpg (18.72 KiB) Viewed 8280 times
Arrow.jpg
... To ...
Arrow.jpg (1.58 KiB) Viewed 8280 times
Primary(Original).jpg
Original Primary disk layout 'before' repartition and partitions resizing (i.e 6 partitions) to...
Primary(Original).jpg (16.53 KiB) Viewed 8280 times
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Postby fortunewill » Fri Sep 03, 2010 10:31 am

Dear Prof,

For better understanding, we need to confirm the whole thing to you.
1. Do you mean your lost data is on Disk 1 which includes a WIN95 partition we saw in the picture? If so, please don't do any change on this disk, no matter deleting data or using Eraser on this disk.
2. Do you mean you will save the recovered files to the G partition on Disk 0 and if the data are not useful, you will use Eraser to permanently delete the data on G partition? So these files will not show in the scan result of Data Recovery Wizard when searching again? If so, we should clarify to you that unless you erase the partition which includes the lost data, our Data Recovery Wizard will always find the same files. Of course, this operation is not recommended for it would damage your data and make it unrecoverable.
If this is your condition, we suggest you use Data Recovery Wizard to scan and recover part of the files, if the files are useless, you just need to delete it (such as using shift + delete) from the partition where you save the recovered files (we think it is G partition according to your description). And then you can do the recovery process again. We also don't suggest you use Eraser in this case to avoid misoperation which will cause the data unrecoverable.
If we misunderstand your problem, please tell us and we will try our best to help you.

Sincerely,
EASEUS Support Team P
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http://www.easeus.com/support.htm
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Postby Prof » Sat Sep 04, 2010 1:51 am

For better understanding, we need to confirm the whole thing to you.

OK.

1. Do you mean your lost data is on Disk 1 which includes a WIN95 partition we saw in the picture?

Yes, I lost all the data of partition L;(Fashion) on Disk 1 - which is now labelled as L;(WinXPClone).

But this is what I did first.
I resized the partitions on Disk 0 from 6 to 3. C: Win2000 Pro, E;WinXP and a big 'unallocated' space. Also, there was D; CD-ROM.


Next, I moved all the data of L;(Fashion) on Disk 1 to the big 'unalloacted' space on Disk 0 (Obviously, by first formatting/defragging/scaning with error fixing etc the 'unallocated' space and perhaps partitioning? so that 'Fashion' data will have its own partition on the unallocated space. But I'm not too sure about the partitioning part though I'm very certain moving all data of F:Fashion on Disk 1 to that unallocated space on Disk 0).

Then, I formatted the old L;Fashion partition on Disk 1 to clone WinXP from Disk 0 to Disk 1. (Hence, old L: Fashion on Disk 1 labelled as L;WinXPClone).

After that, I renamed the CD-ROM drive from D: to X/Y/Z or something and then resized the unallocated space (NOW called G) on Disk 0 to create a PagingFile partition called, PagingFile(D; ) on Disk 0.

Again, I then, moved data (Fashion) of G on Disk 0 'back' to various places on Disk 1 (including some onto its former and original place L;Fashion but then called L:WinXPClone and occupied by WinXP OS etc). I named these folders/files as Fashion1 on one partion, Fashion2 on another partition, Fashion3 on yet another, Fashion4 etc... all on Disk 1.

This was because I wanted to 'increase' the partition size of the PagingFile (D; ) on Disk 1 from 2GB to 5GB, after looking into some parameters on 'Performance' under Admin Tools.

Finally, after finishing resizing the PagingFile (D; ) on Disk 0 etc, sometime later, I 'gathered' all those Fashion1, Fashio2, Fashion3, Fashion4 etc folders/files from 'all' Disk 1 partitions and moved them on to a 'single' folder called Fashion. I can still remember very well by doing this. And that folder, I think, was somewhere (again, probably on its own partition?) on G; on Disk 0 - since there was not any single and 'big enough' space on any of the partitions on Disk 1.

...
To cut the long story short, the next thing I knew was that 'Fashion' folder/partition was completely missing! I only discovered this after trying to save a 'fashion' file into that folder! Typical, innit, loool.


As I mentioned before, the only other cause that I can, remotely, think of was:
3) our area had a power cut while I was using the PC, though I was not working with that missing Fashion folder/partition.
Nevertheless, I'm not sure whether the folder/partition even had existed prior to the power cut or just disappeared afterwards.

If so, please don't do any change on this disk, no matter deleting data or using Eraser on this disk.

Absolutely. This is the ONLY hope that I have left as it's the only place that I may be able to recover data from esp L; WinXPClone, the former L;Fashion partition - though I formatted it before the WinXP clone! M:Graphics may also yield few things (some of theose Fashion1, 2, 3, 4 etc). I had no luck with G: on Disk 0. DRW did not recover much frome there except the usuall Windows stuff... probably because I had resized, formatted etc a number of times!


2. Do you mean you will save the recovered files to the G partition on Disk 0...

Precisely. No hope of any more data from G: And whatever found from there, mainly OS stuff, I already saved onto a third HDD that's now disconnected from the PC.

...and if the data are not useful,you will use Eraser to permanently delete the data on G partition?

Correct. Now, which partition is being overwritten? G or one of the other partitions where the data, now being deleted from partition G, was originally recovered from? This is the answer I need before I 'anything'.

So these files will not show in the scan result of Data Recovery Wizard when searching again?

That's right.

If so, we should clarify to you that unless you erase the partition which includes the lost data, our Data Recovery Wizard will always find the same files.

This is the very thing I was trying to avoid! Hence, the sole use of Eraser.

(we think it is G partition according to your description).

Yeah, G will host all found stuff. There is no any other space big enough for all this.

And then you can do the recovery process again.

What? G is now filling up, my friend! loool.

We also don't suggest you use Eraser in this case to avoid misoperation which will cause the data unrecoverable.

Alright. I will leave Eraser alone and forget about installing it. May be later for other things. Stick to 'recover' then 'delete' and then 'empty' from the recycle bin?


Thanks.
Last edited by Prof on Sat Sep 04, 2010 7:12 pm, edited 1 time in total.
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Postby Prof » Sat Sep 04, 2010 5:42 am

...we suggest you use Data Recovery Wizard to scan and recover part of the files, if the files are useless, you just need to delete it (such as using shift + delete) from the partition where you save the recovered files...

Sorry, I don't quite get this.
If I recover it first, save, then delete it after viewing it, then DRW (as you pointed out) will find it again!
i.e DRW is 'recyling' the same stuff... find, delete, find (deleted)... and so on.

In addition, 'lost' data is only visible under DRW while in 'recovery'. Can you delete it under DRW without having to save it first (eg if deemed unwanted during preview etc)?

Alternatively - if I save everything first berofre I complete all scans - partition G is filling up with all sorts of data (unwanted, less usefull, good...) from all partitions

I need to reduce the search/find time, as well as, how much data is recoverable every time I do 'Completely Recovery from a partition.

Or am I missing something?
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Postby Yang Bo » Sat Sep 04, 2010 4:33 pm

Dear Prof,

We are sorry for your trouble.
According to screenshots and your description, we find that you reformatted your disk 1 a number of times and your original files on the F partition (L partition currently) had been overwritten; it's difficult to recover lost data. In this situation, we suggest you install our product on the disk 0 to try to recover again, you can choose "Partition Recovery" to get your data, please refers to:
http://www.easeus.com/datarecoverywizar ... drives.htm
When you finish the scan, if you don't want to save the unwanted files, you can use the search method to filter all found files so that you can find the desired files, and only select them to save to a safe place. We suggest you save the files to another external disk. You can filter the files by their file name/size/type/date, etc. (for example, you can type '*.jpg' to find all the '.jpg' files through "Search files" function)

Sincerely,
EASEUS Support Team Z
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http://www.easeus.com/support.htm
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Postby Prof » Sat Sep 04, 2010 7:29 pm

According to screenshots and your description, we find that you reformatted your disk 1 a number of times and your original files on the F partition (L partition currently) had been overwritten; it's difficult to recover lost data.

I only reformatted the partitions J:Win2KClone (formerly Win2000) and L:WinXClone (formerly Fashion). I did not touch anything else as I only needed to clone these OSes to the secondary disk, Disk 1.

In this situation, we suggest you install our product on the disk 0 to try to recover again,

That's where I installed both EPM and DRW.

you can choose "Partition Recovery" to get your data,

I tried this with the demo version before and I think it did not recover much but came up with loads of previous partitions. It is also took some time...

When you finish the scan, if you don't want to save the unwanted files, you can use the search method to filter all found files so that you can find the desired files, and only select them to save to a safe place.

OK, I'll try this. But bear in mind 'preview' is still limited to some files... will not preview all file types.

We suggest you save the files to another external disk.

Unfortunately, I haven't got one at the moment as I always use internal HDD (IDE interface).
And I can't justify buying one now unless I'm sure that I will find some usefull data to save on it.

You can filter the files by their file name/size/type/date, etc. (for example, you can type '*.jpg' to find all the '.jpg' files through "Search files" function)

I have done this a couple of times. But DRW will only preview JPEGs, Word etc. Most of my lost files are PSP, PSD, PDF, HTML... and so on.
Which means I have to save all found data first in order to review it.


Once again thank you for your help.
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Postby M.Mao » Sun Sep 05, 2010 9:25 am

Dear Prof,

Just as our previous reply said, our product doesn't support previewing PSP and PSD files. So we think you have to save these files to a device which does not contain the lost data. Then try to open them by proper application.

Meanwhile, if you choose "Partition Recovery" module, it will perform 'Quick Partition Searching' first, and then list the lost partition(s) on your hard disk (if you lost partition before). You can try to find data from the lost partitions first; if you failed, you can go back to the lost partition's list and check "Full Scan" above to perform 'Intelligent searching' (or restart the scan and 'Cancel' the 'Quick Partition Searching').

We suggest you just refer to our previous reply to help you. Hope you will solve your problem soon.

Sincerely,
EASEUS Support Team E
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http://www.easeus.com/support.htm
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recover inquiries

Postby jesus » Fri Sep 10, 2010 6:05 pm

Hi EASEUS support team,

can i check with u if i can still recover data even if the drive had been overwritten,

scenario:
drives partitioned in to 2 (c: / d:)
purpose : need to recover files that has bee cut or deleted from d:
drive d: has been recovered already and put to drive c:
drive c: run recovery to this partition and put to drive d:

is there any chance to see the data (original) again from drive d: since i run also the recovery from drive c: and put into drive d: seems that the drive d: is already overwritten? and i cannot see the data again once i run the search mode from drive d: only those files that been generated and data dump to drive d: is only generated.

thanks
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