Logical Failure – Partial Overwrite

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This describes a hard drive data recovery task where new data has been added to the hard drive, having previously encountered corruption of some sort.

Possible sources of corruption include:

  • Virus/malware propagation
  • Disk formatting (accidental or deliberate)
  • Partition corruption due to partition manipulation
  • Corruption of the operating system or of the master file table, where all file entries are stored.

The best chance of data recovery from such hard drives is attained when no new data has been written to the hard drive after the failure.  When new data has been added (e.g. re-format or activation of recovery mode), you should expect a certain amount of contamination of your original data, rendering some files unopenable.   Generally speaking, the more new data written to the hard drive, the lower the possibility of a successful recovery.  On the balance of probability, overwriting tends to affect large files (photos, videos etc) more than small ones (e.g. Microsoft Word/Excel files).

These types of data recovery tasks do not involve cleanroom handling, as the drives do not need to be physically opened.  CDS operate a wide range of high-end logical recovery software tools to deal with these types of failures.  Due to fragmentation and the inherent random nature of overwritten locations, the user can expect a significant level of file corruption in the recovered data.