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How does Recuva actually work?


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#1 OFFLINE Moinul

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Posted 21 September 2007 - 08:26 PM

Hi all,

I'm a big fan of your work. The CCleaner program has been a really good program and I use it everyday.

Recuva on the other hand has been very difficult to use. Well, not to use but to understand how to use is complicated. I can recover my files which is good but I can't use them. I accidently deleted a song that I shouldn't have and I used the Recuva program to retrieve it. I got it back but it does not work. I have tried all different sorts of Media Players such as WMP 11, RealPlayer 11, iTunes 7, etc. and it still does not work. its a normal MP3 file.

Can someone please help me out? I'm getting very frustrated. Not because I lost this one song but because theres many other songs that I need back as well.

Thanks,

Regards,

Moinul

#2 OFFLINE theymos

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Posted 30 September 2007 - 10:30 PM

When you delete a file from the recycle bin, the computer marks the space it occupied as "unused", and any application can write to that space. If you have a large hard disk and a decent amount of luck, by the time you run recuva, none of the file will have been overwritten. If part of the file has been overwritten, it will (as in your case) not work at all or (usually with large movie files) part of it won't work. That's just tough luck; there's absolutely nothing anyone can do, sorry :(

#3 OFFLINE Keithuk

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Posted 29 October 2007 - 03:45 PM

I accidently deleted a song that I shouldn't have and I used the Recuva program to retrieve it. I got it back but it does not work.

Which version of Recuva are you using?

There appears to be a bug in the newest version for recovering jpg's. ;)

JPG partial recovery
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#4 OFFLINE Rekrul

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Posted 10 November 2007 - 09:38 PM

Recuva on the other hand has been very difficult to use. Well, not to use but to understand how to use is complicated. I can recover my files which is good but I can't use them. I accidently deleted a song that I shouldn't have and I used the Recuva program to retrieve it. I got it back but it does not work. I have tried all different sorts of Media Players such as WMP 11, RealPlayer 11, iTunes 7, etc. and it still does not work. its a normal MP3 file.

Can someone please help me out? I'm getting very frustrated. Not because I lost this one song but because theres many other songs that I need back as well.


Is the drive that you're trying to recover files from formatted as FAT16 or FAT32? If so, and if the drive is at all fragmented, you can forget about recovering any deleted files from it. At least if they're bigger than a few K.

The FAT file systems were designed by short-sighted authors. Basically, they have no provision for recovering deleted files. The designers apparently thought that the recycle bin would be all the safety net users would need and didn't account for files being deleted directly from the drive.

In the FAT file systems, the directory entry stores the file's name and the pointer to the first block on the drive. The pointers to the rest of the blocks used by the file are stored in the File Allocation Table (FAT). When a file is deleted, Windows erases the FAT entry for that file. So recovery software can find the start of the file, but there is absolutely no way to find the rest of it. Most programs will guess based on where Windows would have stored the rest of the file on a completely defragged drive. If the drive was at all fragmented then there is about a 99% chance that the program's guess will be wrong and it will "recover" unrelated data from other files.

The only way to ensure that you can recover deleted files from a FAT drive is to run defrag after every single file operation so that no file will ever be fragmented.

I call the authors "short sighted" because all it would have taken to prevent the above is to reserve a few bytes from each block to serve as a redundant pointer to the next block in the file. Then even if the FAT entry was erased, the recovery software could just follow the links.

Supposedly, they got a clue when they designed the NTFS file system and made it so that even fragmented files can be recovered as long as they haven't been overwritten.

Data Recoverability