The Master File Table (MFT) of the NTFS volume is not contiguous, but is stored in the several fragments.
By design of the NTFS, the MFT Mirror (copy of the several critical MFT entries) is stored separately from the rest of the MFT.
Thus, at least two fragments of MFT are stored on the volume.
More complex layouts are possible due to additional fragmentation, typically when a volume gets filled near its capacity.
Additionally, several MFT entries may be damaged, thus splitting a contiguous MFT fragment in two.
This fragmentation must be resolved and the contiguous representation of the MFT rebuilt.
This is required to
- recover large and/or heavily fragmented files,
- properly parse and rebuild the folder and file tree.