Deleted or overwritten data
If you have repartitioned, reformatted or deleted data from the drive.
In these situations we must scavenge the drive for all possible data.
The yield of good versus corrupted recovered files is dependent upon a few things such as the condition of the MFT, FAT or Inode Tree (where they overwritten?), the amount of new data written to the drive after the fact, and how often the drive was de-fragmented. For example, a drive that was freshly de-fragmented before the accident may yield 95% good files. A drive that has never been de-fragmented may yield 95% corrupted files.
In any case, the scavenging routines must be run to get anything back. This is the only type of drive recovery procedure that cannot be guaranteed…we will get everything possible.