Why it is Impossible to Recover Data From an Overwritten Hard Drive?

Written By Isha Rikhi
Approved By Rohit Arora
Updated on 27 Feb, 2023
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In this present digital era, Data Loss is a common occurrence. When this happens, the only need is of Recovery. Thanks to the Data Recovery software, it is no more a tedious task nowadays. Using an ideal recovery software, we can easily regain lost data. The consideration point here is that lost or deleted data should not be overwritten.

So, if you are having a query why we cannot Recover Data from an Overwritten Hard Drive, then your search ends here!

Simple Reason: System does not retain previous state trace once it has been overwritten.

Indeed, the response is irksome, but the truth! It outlines why it is impossible to recover data from an overwritten hard drive.

Data loss is a common occurrence in this fast-evolving digital scenario. Fortunately, thanks to Data Recovery software, it is also possible. You can define these software as shoulder programs of this IT rampant era. Typically, deleted data is recoverable since when you delete the data it does not gets deleted in actual, only the information where you stored it has been removed.

Let us dig deeper and get some insights of data storage, formatting, deletion on a hard drive.

How is Digital Information Stored?

Information stored digitally is in the form of bytes, and each of these byte includes 8 bits. The value of these bits is either 0 or 1. You can define this approach of data storage as the Binary Numeral System. All the information stored on the Computer is in the Binary Code form i.e. string of 0s and 1s.

How Does Hard Drive Save Data?

In simple words, information is saved non-volatile and magnetically. The reason being, you require no power to maintain the saved data. Each magnet has a Plus and Minus Pole that represents the Binary Code. Platter, HDD Storage unit includes a ferromagnetic surface that gets subdivided into magnetic domains, the small magnetic regions. HDD uses magnetic domains directional magnetization to store data. You can magnetize each magnetic domain in any of the two possible directions and represent values from O & 1 subsequently.

How Is Data Reordered on an HDD?

In general, there are two different technologies for HDD Data Recording —

Firstly, Recording Layer was Oriented Parallel to the Disk Surface. In this, Binary code used to represent directional magnetization left vs. right (longitudinal recording).
Secondly, Magnetizing Segments Vertically. In this, Data is written up vs. down in perpendicular recording. With this, you get larger storage capacities as well as closer magnetic domain spacing.

How is Information Saved in Random Access Memory?

Inevitably, the manner of data storage is same i.e. Binary Code. The reason being, RAM is an amalgam of integrated circuits including Transistors and Capacitors, and even they save data in bits form. The principal difference is here the Storage type is volatile. Thus, when you remove power, information is lost.

Now, you must have got a sound knowledge of how Data Storage takes place.

Next, the big question what happens when data becomes inaccessible?

Scenario 1: When Data Has Been Deleted

If we talk about RAM, when we remove data from it, it actually vanishes as the organizational structure is very flat. However, the condition with HDD is entirely diverse. The reason being, it stores information in two approaches. Firstly, on the Magnetic Hard drive, physically, and secondly, by File System management. The File System approach creates data table indicating the data’s exact location. Using the table, the operating system searches the files and compiles large files pieces altogether.

Now, when you delete a file, only the data stored in the file system’s table gets removed, and data’s physical location remains untouched. Thus, using a professional data recovery tool like Stellar Data Recovery Professional, you can recover it when required. However, the point to consider here is since the table is marked as vacant thus can be rewritten by the operating system and once it has overwritten, the information previously saving on it gets terminally deleted, hence cannot be retrieved.

Scenario 2: When HDD Has Been Formatted

In simple words, Formatting is a process to set up empty File System. It is also well-known as Quick Formatting as you do not need to scan the hard drive for defects. So, when you format the Hard Drive, its data is not physically deleted.

Typically, it is set up from a scratch, re-organized, and the table including information where files are saved has been reset. So, unless and until you won’t change the settings and file system, data saved on it remains untouched and can be recovered using the recommended software solution like Stellar Data Recovery Professional for Windows. But, if in case if any the two has been altered because of overwriting, it becomes almost impossible to retrieve.

Why Can’t You Recover Data from an Overwritten Hard Drive?

The Hard Drive Recovery from Overwritten Hard Drive is impossible as it is an irreversible process. The reason being, when you overwrite the data, you re-magnetize the HDD magnetic domains. Hence, you physically eliminate data formerly saved on the location.

Indeed, few residual physical changes traces are left behind in magnetization and can assist in Partial Restore. But, it demands usage of Magnetic Force Microscope and probability of successful Data Recovery is almost negligible. In essence, it will not be erroneous to state that presently there is neither any Software nor any other technical approach for restoring overwritten data.

Conclusion

The first and the foremost solution to protect you from data loss and its associated hassle is Backup. And in case, if you do not have the backup, go for a professional data recovery solution using software and service, depending upon your need. The only point to take into account is that it should not be overwritten as both software and service also fail to recover data from such instances.

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About The Author

Isha Rikhi

Isha is a technical blogger and data recovery expert. She has experience in Windows data recovery. She writes about technical tips and tutorials.

32 comments

Minnie Gaul says:

May 29, 2019 at 10:34 pm

Hii Isha

Good clear article. I wish i’d read this before reformatting an external hard drive and deleting files I meant to keep. . I saved some new data on to the reformatted disk. Are the old deleted files still likely to be unrecoverable even with just a partial overwrite? Thanks

Reply
1. Satyeshu Kumar says:
  
  May 31, 2019 at 6:27 am
  
  Hello Minnie,
  Data recovery possibility for overwritten data is very less as new data overwrite the old data. Still, you can try Stellar Data Recovery Software in order to check the data recovery. If you find your files in preview so you can recover it. Thanks
  
  Reply
ronaldo says:

April 20, 2019 at 9:40 am

i want to sell my old hdd ( 2 tb ) to buy another big size one ( 8 tb )
what can i do to make my old hard disk unrecoverable , and i want to ask if i re partition my old hdd it is enough or not .

Reply
1. Satyeshu Kumar says:
  
  April 29, 2019 at 10:46 am
  
  Hello Ronaldo
  If you are selling your old HDD (2TB) and want it unrecoverable so we understand your needs. But if you do the repartition still it can be recover by the software. But overwritten data cannot be recovered by any software. Because the data is store in bit wise. Another option which I will highly recommend to you use BitRaser software to erase everything from your HDD and your data will be permanently deleted from this drive and cannot be recovered by any software tools. BitRaser supports 27 International erasure standard and perform high speed eraser up to 32 hard drives simultaneously. You can see more information about this powerful product on following links:
  BitRaser
  
  Reply
  1. Ronaldo says:
    
    May 26, 2019 at 4:58 pm
    
    firstly : many thanks to you for your replay . especially when you say that ” if you do the repartition still it can be recover by the software ”
    
    secondly : BitRaser is not a free program and i want any free program or any program which can i find it on torrent .
  2. Satyeshu Kumar says:
    
    May 27, 2019 at 9:40 am
    
    Dear Ronaldo,
    Free software doesn’t provide any certifiable proof of 100% safe data erasure standards. We also would like to inform you that use of a crack license key or torrent is against the data safety policies.
Conundrum says:

January 20, 2019 at 9:17 am

Interestingly I once did recover data from an overwritten (zerofilled) 1TB laptop HDD. It was not clear why this happened but possibly related to low power during the zerofill as it showed a few unwritten bytes with original data fragments totalling about 4MB.
Ways to tell: doing a read test showed areas that took an abnormally long time to read data and also it later failed again during other tests.
This also to some extent applies to SSDs and memory cards.

It could also be that unless you specify it, wipes do not touch the spare sector pool of reallocated sectors.

Reply
1. Isha Rikhi says:
  
  January 22, 2019 at 4:37 am
  
  Hello Conundrum,
  
  Thanks for sharing your wonderful experience.
  
  Reply
Ayush says:

January 9, 2019 at 7:07 pm

I have a Pentium 4 computer in which I had saved some very important files which got deleted accidentally, at that time back in 2013 I had windows xp operating system in my computer and after that i installed windows 7 operating system in my computer, before installing windows 7 in my computer i was not aware about the data recovery tools but now since I know then i tried to recover my files which got deleted at that time but it showing as overwritten file,.
so please ma’am help me out to recover those delete files because they are really very important files for me

Reply
1. Isha Rikhi says:
  
  January 10, 2019 at 3:27 am
  
  Dear Ayush,
  
  Sorry to hear about the issue
  Generally, it was believed that overwritten files can’t be recovered by any software, since all the data is overwritten with random 0’s & 1’s.
  
  But sensing the severity of the data, you can try your luck using advance Stellar Data Recovery Professional for Windows software. Just free download the software from the below mentioned link and try to scan the hard drive and check if the lost data is available in Preview, if it is available then only it can be recovered.
  Download Link
  
  Hope my solution bring some relief to you.
  
  Reply
Jeffrey Woods says:

July 29, 2018 at 10:01 pm

I have some old jpeg files that were overwritten. The recovery software i was using can see that they are present, but when opened they arent viewable. Is there any hope of recovering?

Reply
1. Isha Rikhi says:
  
  July 31, 2018 at 3:58 am
  
  Hello Jeffrey,
  
  The chances of recovery from overwritten files are slim to none from all major recovery software.
  
  Reply
Laliy says:

July 19, 2018 at 7:54 am

I am working in mnc as desktop support engineer.i have formatted c drive having macfee encryption.and now i am unable to decrypt the d drive…and i dont have key…now it fucked with my first job….even stellers are helpless…

Reply
1. Isha Rikhi says:
  
  July 25, 2018 at 2:20 am
  
  Hello Laliy,
  
  We would like to inform that our software could only help in recovering the lost or deleted data. It does not decrypt the drive or data. The scanning could be performed on the encrypted partition if the preview is available recovery could be done else not.
  
  Reply
Gursewak Singh says:

May 16, 2018 at 9:38 am

hello Ma’am
I am Gursewak Singh from Jalandhar, Punjab. Few days ago New SMPS (Power Supply) was provided by computer shopkeeper in my Desktop (Windows -7 Ultimate ; 32 Bit). As he started the PC , He told me about OS Corrupt. After my approval, he installed Windows -7 Ultimate in my PC. But as he reboot the PC it shows My F Drive corrupted. The properties of F Drive shows 0 bytes used space and 0 bytes free space. I was unable to access F Drive.Then he perform quick formatted the F Drive. All data was lost that was too important for me as it includes Pics,Docs.,pdf files,audio & Video files. Due to lack of knowledge I overwrite some data on F Drive. Now I come to know that those files could be recovered with Data recovery s/w. I tried approx 4 types of Data recovery s/w. All s/w recovered my data but unable to access it as data was corrupted. What to do? Is it possible to repair all corrupted data.
Pls Do reply me via email.
Regards
Gursewak Singh

Reply
1. Isha Rikhi says:
  
  May 18, 2018 at 3:37 am
  
  Hello Gursewak,
  
  Thanks for contacting Stellar Data Recovery
  
  Stellar Windows Data Recovery Professional allows you to recover the data from the volumes which are inaccessible.
  
  We recommend you to download the demo version of the software from the below mentioned link:
  Download Link
  
  After installing the software, kindly run it and perform the scan using ‘Can’t Find Drive’ option to search for the volumes. Once the volume is listed then please run the scan to check the possibility of recovery.
  
  Reply
John Kepler says:

March 5, 2018 at 10:44 am

Thanks for the post. Even I lost some of my important audio files in past due to overwritten of data. I really wish if I could found this article earlier. All the Best

Reply
1. Isha Rikhi says:
  
  March 6, 2018 at 4:29 am
  
  Hello John,
  
  Thanks for narrating your story. We request you to please share this post from your various social handle.
  
  Reply
Dennis Akai says:

August 28, 2017 at 10:11 am

Recently, I need to reinstall the windows due to system internal error. Please suggest, how can I recover my previous data back?

Reply
1. Jyoti Prakash says:
  
  August 29, 2017 at 4:44 am
  
  Hello Dennis,
  
  We recommend you to try the demo version of Stellar Data Recovery Professional.
  
  Kindly install the software from the below-mentioned link:
  
  Download Link
  
  After installing the software, please follow the below-mentioned steps to perform the scan on your drive:
  
  1. Run Stellar Windows Data Recovery.
  2. From Select What to Recover screen, select the type of data i.e. Everything, Documents, Folders & Emails or Multimedia Files, you want to recover.
  3. Click Next.
  4. On Select Location screen, select Can’t Find Drive from Other Locations
  5. Now click on ‘Scan’ button.
  6. In the Select Drive section, all the hard drives connected to the system are listed with their details. From this section, choose a hard drive you want to scan for lost partitions and click Search. A scan for lost or deleted partitions will be performed in the selected disk or drive.
  7. Any ‘lost partition’ detected, will be listed in the Partition Found section.
  8. From the list of partitions found, select any desired partition and click Scan to continue with the recovery process.
  
  Reply
Tom Natal says:

July 25, 2017 at 11:56 am

I wish that I could read this blog a few days ago. I only get to know, about no chance of data recovery from overwritten hard drive once I paid $50 to the data recovery expert. Since most of the important files are overwritten with new files. With no backups, all the data is lost. Thanks for this awareness

Reply
1. Jyoti Prakash says:
  
  July 26, 2017 at 4:42 am
  
  Hello Tom,
  
  Don’t feel sad. You may further generate awareness by sharing this post among your friends and colleagues.
  
  Reply