Do we actually delete files permanently? Wanted to know why some permanently deleted files are not recoverable. This blog explains the basics of file deletion including what happens when a file is deleted, where and how data is stored in a storage disk, what makes data recovery feasible, and software solution for data recovery. Read on to know more.
Why is File Deleted?
You delete files. The reason for deletion can be for getting rid of unneeded or obsolete files, removing the redundant occurrence of files, or to freeing up disk space. Whatever the reason be, you delete files in two ways one temporary and other permanent.
What is Temporary File Deletion?
In a temporary file deletion process, you select the files you want to delete, open the popup menu by right-clicking on the selected area, choose to Delete; or you can select the files and press the Delete key from the keyboard. The deletion is temporary as you can restore these files from the recycle bin. Just open the recycle bin, select the files, and click Restore.
What is Permanent File Deletion?
In a permanent file deletion process, you select the files you desire to delete and press the key combination Shift and Delete; or you select the files from the recycle bin, open the popup menu by right-clicking on the selected area, choose Delete, and click Yes on the confirmation dialog box. The deletion is permanent as there are no means through which operating system can restore the files.
Permanently Deleted File in Recoverable State
If you permanently delete a file by removing the file from recycle bin or using the shortcut key ‘Shift + Delete’, the utilized space is marked as free for future reuse by removing the reference to the file in the Master File Table (MFT). The file’s data in the form of bits are present in the allocated sectors of the hard disk drive and are not zeroed by the Windows operating system. The reason is updating the MFT table is almost instantaneous, while zeroing of the assigned sectors require a processing time of CPU, which slows down other activities of PC – hence not implemented. The sectors containing the data is really unharmed when the data is permanently deleted but has no owner. These permanently deleted files are in recoverable state and can be recovered by a data recovery tool.
Permanently Deleted File in Irrecoverable State
If you start using your computer after permanent file deletion, then there are chances that operating system might overwrite on the deallocated sectors where the actual data is residing. In this situation, the file is in an irrecoverable state. No software can recover the file, because the bits are changed and has lost its inherent meaning. Realize that anything (audio, video, image, text, etc.) can be represented by bits, but when bits are manipulated operating system cannot interpret the same as before. This is the reason why some permanently deleted files are not recoverable.
Recovery Process of Permanently Deleted Files
The process of recovery involves scanning of the MFT. If no file is using the sectors that were previously allocated to the deleted file, then a recovery software can extract the file from these sectors by reading the start till end bit.
Precautionary Measures
When you have permanently deleted your files, later realized that it was essential, and you wanted to recover them, then just stop using your PC. This will ensure there is no accidental overwriting.
How to Recover Permanently Deleted Files
If the data you deleted is present in a different volume where Windows operating system is installed, then you can download a data recovery software such as Stellar Windows Data Recovery Home in your system drive (C: Drive). Install and run the software to recover the permanently deleted files. If the files you have permanently deleted is on your system drive, then you cannot use the same drive for performing data recovery task as it might overwrite the permanently deleted area. In that situation, get a secondary computer to download and install the data recovery software there. Connect the affected computer as a slave to the secondary computer. Run the software and carry out tasks as per the instruction of the software’s wizard to get back your data.
Wrap Up
Some permanently deleted files recovery is not possible because the allocated sectors containing the well-formed bits are changed. The interpretation that the operating system can make out from the manipulated bits including the header and footer that signify the type of data is modified and is now representing the information of the newer overwritten files.
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