MFT (Master File Table)

The Master File Table (MFT) stores the information of every file and directory on a NTFS volume. NTFS reserves first 16 records of the table to store some critical information. The first record of this table is the Master File table. A MFT record is followed by a MFT mirror record. The boot sector holds the locations of the data segments for MFT and MFT mirror file.

NTFS reads the MTF; if it is not available (on corrupting) then it reads MFT mirror record. The first record of MFT mirror is identical to first record of MFT.

As and when files are stored on NTFS volume, entries are made in MFT, thereby increasing the size of the MFT. On deletion of files from NTFS volume, the entries from MFT are released and marked as free. This free space could be used later on addition of new file entries.

In Service Pack 4 for Windows NT 4.0, a new registry parameter was introduced to increase the percentage of volume that NTFS could reserve for its MFT. The attributes of each file are store d in the MFT.

MFT should be kept contiguous for better performance.

NTFS MFT Zone Reservation – It takes a value in the range of 1 to 4. The maximum value is 4 and minimum value is 1. On supplying invalid value or no value, NTFS sets the default value as 1 to this parameter (NtfsMftZoneReservation). MFT Zone will not be utilized, unless the rest of the space is totally consumed.

dir /a $mft  -  This command yields the current size of the MFT on a Windows NT – based computer. The command should be typed on NTFS volume.

Corruption of Master File Table

When MFT gets corrupt, NTFS synchronizes the copy of MFT i.e. MFT mirror. Sometimes when NTFS is unable to synchronize; CHKDSK (check disk) utility can be used. In certain cases the MFT when severely and even CHKDSK fails to repair MFT, NTFS recovery software can be used.

Related Information

Recover files from NTFS
The Master File Table can be damaged due to virus attack, resulting in missing / lost files and folders from NTFS partition. You might lose important files under such condition. You need not worry about the loss, as the article provides an easy recovery option.