Format Recovery – Retrieving Data From A Formatted Hard Disk

by Rod Dunne on September 22, 2010

in Data Recovery

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Performing a format recovery is actually one of the simpler home computer repair tasks that you can complete by yourself. This is thanks to the range of applications which make it very easy to find your lost files. Here, we’ll look at how to use these tools, and some of the factors which will affect how successful any file recovery tools will be.

How is format recovery possible?

Formatting a hard drive will not actually completely wipe the documents from your hard disk. When you store the document on the hard drive, it is saved as data clusters around the disk. The file allocation table keeps a record of all the documents on your hard drive along with the addresses of their associated data clusters. The formatting process will only clear down the file allocation table, leaving the data clusters unharmed. File retrieval tools can recover formatted hard drive data simply by identifying and reassembling these clusters.

However, as these files are no longer visible in Windows Explorer (because the file allocation table has been cleared down), you will need to use format recovery software to scan the drive.

Note that if the format recovery process is held up because of Windows system exceptions stating that the file system has reverted back to a raw format, then see our article on raw data recovery to show how specialist tools can be used to bypass this problem.

How format recovery software works.

All format data recovery applications work in a similar manner. The standard process is usually something like the following:

  1. Install and start-up your format recovery software. Some suggested applications that you could try using are Remo Undelete.
  2. When prompted, select the formatted drive for analysis and start a scan.
  3. The program will scan the hard drive for lost data clusters, see if it can assemble these into recognizable documents and present back to you in a flat list of found files (i.e. no directories/folders).
  4. Pick the files you want to copy and transfer them over to a new location (CD/HDD).

Suggested Tools:

Factors affecting a post format data recovery.

Unfortunately, the format file recovery software will not succeed in finding all your documents, all of the time. There are some factors which can hinder how many files you will find, if any at all.

On some occasions, the formatting process may actually fail resulting in the memory no longer using NTFS/fat 32 as it is chosen file system format. This will result in the drive reverting back to using the raw file system format. unfortunately, many data recovery applications cannot read raw partitions so you will have to specifically look for raw recovery tools that can analyze a more partition.

The worst case scenario is when the formatting process includes a data cleansing, or data cleaning, sweep of the hard drive. In this case, a format file recovery tool will generally not find any documents on the hard drive as data cleansing will have overwritten all the original data clusters. You could consider forensic level data recovery software tools (as detailed in our article on how to recover overwritten file contents) which can retrieve overwritten files by using data shadows (fragments of files versions) on the hard disk memory.

A less severe case involves the continued usage of the hard drive after formatting has occurred. Simply by saving files or installing new applications on the hard drive you will be overwriting the original formatted documents, and their data clusters. This will be a slow process by which the original documents are gradually lost making data file recovery of even partial results even difficult.

Finally, as the format recovery software has to piece together data clusters on the disk, like an elaborate jigsaw puzzle, they cannot depend upon the file allocation table to work out how each cluster is associated with another. Therefore, it is up to the application itself to understand how each of the pieces can be reassembled back into proper documents.

Some tools are better than others at doing this. As a result, you may find that each application can potentially return a different list of found documents, so always try using the free scan provided with these format data recovery tools to establish if they are capable of finding your documents before committing to a purchase.

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