Data Recovery USB: Simple Guide To Using Software To Recover Lost Files

by Rod Dunne on September 10, 2010

in Articles, Data Recovery

  • Share
  • Share

One of the more common PC repair activities that individuals encounter is trying to find files that have been deleted, formatted or corrupted on a hard drive. In terms of data recovery USB key devices can be treated in a similar way to hard drives when finding lost files. Here, we’ll show how recovery software can be used to get your files back from USB/flash memory.

Data Recovery USB Flash Devices: Using Software

When files are deleted they are not completely cleared from memory, their location indexes are merely not being shown to you in Windows Explorer.

To scan for and find the files you will need a data recovery tool (e.g. Remo Undelete which works on hard drives and USB flash memory).

The process of data recovery from USB memory is then fairly simple:

  1. Start the recovery software. Select the USB device for analysis.
  2. The application scans the memory for fragments of data, compiles these into actual files and presents you back a list of found files.
  3. You copy whichever files you need to the hard drive. You’re done!

Tip: Some applications used for USB protection (password protecting contents) can also synchronize/backup your data as a value added feature meaning you could recover USB contents from a cloned backup instead of resorting to file recovery programs.

How Is Data Recovery From USB Keys Possible?

Deleting a document does not actually clean it from the USB memory. All it really does is stop you from seeing the file in a Windows Explorer directory.

Each document is saved to flash memory as several data clusters placed all over the memory chips (i.e. not always co-located). As flash memory uses the FAT-32 file system, same as Windows, your document will have an index reference in the file allocation table (FAT). The FAT lists all documents on memory along with their directory attributes and which clusters in memory actually store the document’s contents.

  • File Deletion: This resets the directory attribute for the deleted document in the FAT. The clusters are left intact, but are available to Windows for reuse (i.e. for saving new files). For more information, check out our post on the deleted file recovery process.
  • Disk Formatting: This clears the FAT of all document references, but still leaves clusters in memory.

So, for file recovery USB data can be found by scanning the USB memory for data clusters and using the FAT to put the cluster fragments back together as documents. If the FAT is empty (e.g. after formatting) then the format recovery software needs to be smart enough to piece clusters together like a complex jigsaw puzzle.

Data Recovery USB Key: Factors Affecting Success

Using software will not be successful all of the time. For file recovery USB data may be affected by the following:

  • Continued usage of the flash key will gradually overwrite the original data clusters.
  • Formatting processes that use a data cleaning/cleansing sweep will deliberately obliterate the data clusters in an effort to wipe all personal data/evidence.
  • Each tool uses different algorithms to consolidate clusters. Therefore, each will find slightly different lists of files.
  • If the file system format has become corrupted then you may have to resort to using raw recovery tools to retrieve your documents, as regular data recovery software depends upon understanding if it is fat 32/NTFS that the USB key is supporting.

When it comes to data recovery USB flash keys/devices have really benefited from their support of the FAT-32 format. This in turn helps make data recovery easier to achieve. However, data recovery from USB drives may not be successful 100% of the time so you should also consider backing up the contents of the drive as a precaution.

Useful Resources:
- File recovery software: Remo Undelete (FAT/NTFS support),
which can provide a free trial scan.
- Backup software: Final Sync (sync files between hardware), iDrive/My Live Drive (online backup data storage service).

Previous post:

Next post: