YES! THEY CAN BE RECOVERED. Surprised? For non-technical individual it would be a surprise. But for those who are techie enough it is not.
How could it be possible?
A computer has what it calls as "File Allocation Table" or "File System". In the earlier versions of personal computer specifically in a Windows computer FAT or "File Allocation Table" is first used. It was succeeded by FAT32 then the latest version is NTFS or "New Technology File System".
NTFS is still used by today's Windows 10.
FAT/NTFS is the one responsible in writing the file you are saving into the computer's hard drive hence the words "File Allocation" and "File System".
Every time a file is saved or erased it is recorded or erased on the computer's file system. The file system then write or erase the file in a several sector on the hard drive.
An allocation table or file system sits on top of a hard drive partition that contains sectors or location.
However, when a file is erased the file system simply tags the sector in a hard drive as "empty" without really erasing the file in the hard drive enabling the computer to write files into that sector again.
Meaning, the file stays physically in the computer's hard drive until it is overwritten by the computer.
With that said, any file can be recovered by a specially designed recovery software. Recovery software scans the whole hard drive to find files that are deleted by the computer's operating system.
How or When a File Can be Recovered
When you save a file on a computer the file will be written in fragments. Meaning to say a portion of a file will be written in various sectors or locations on the hard drive.
When you erased a file now and you also erased it in the Recycle Bin there's a high probability that a recovery software will recover it until a file has overwritten the sector/s wherein the file resides.
When a File is not going to be Recovered
If a file is erased few days ago on your computer and you are actively using the same computer in saving files for a few days now there's a high probability that the file you erased will not be recovered because the file's physical location (sector) could already be overwritten while you are saving files on the computer.
Good Practices for High Recovery Rate
If you are using USB and you accidentally erased a file and you want to recover it do not save anything on the USB as it might overwrite the location where your file resides.
What to do when a File is Delete and You Want to Recover it.
Do not save or write anything on the USB or Hard Drive where the file is deleted. Surfing the internet requires saving of the website's files, so it is also not recommended until you recovered your file.
My Experiences
There was a time when one of my office mate approached me if I can recover his file on his USB flash drive. He said the USB suddenly becomes empty when he last used it in his computer.
I asked him immediately this one question "have you tried to save anything on that USB after you found it to be empty?" He said, No.
Why I asked him the question? Because if he already saved some files on the USB there's a chance that the sector wherein the missing files reside can be overwritten.
If it is indeed overwritten his files cannot be recovered anymore.
Secret of the Trade
I have just learned this philosophy along the way while working as an I.T. professional for more than a decade now. If you know how to recover a file do not help everyone that seeks your help.
The skill together with the software that you are going to use sometimes deserve a professional fee. Do not let it abused.
You can be kind sometimes. But sometimes your kindness can be abused to. Think, it's your call.
