A Full Introduction to NTFS Master File Table (MFT)

What Is MFT?

The Definition of MFT

What is MFT? The NTFS file system contains a file called MFT, or master file table. There is at least one entry in the MFT for every file on an NTFS file system volume, including the MFT itself.

All information about the file, including the file’s size, time and date stamp, permissions, and data content, is stored in the MFT entry or in the MFT external space described by the MFT entry.

The Structure of MFT

More entries will be added to the MFT as files are added to the NTFS file system volume, and the size of the MFT will increase. The MFT entries are marked as free and can be reused after files are deleted from NTFS file system volumes.

The master file table allocates a certain amount of space for each file record. The attributes of a file are written to the allocated space in the MFT. Small files and directories (typically 512 bytes or smaller), such as the file illustrated in the next figure, can entirely be contained within the master file table record.

However, the disk space allocated to these entries is not reallocated and the size of the MFT does not decrease.

The NTFS file system reserves space for MFT to keep it as continuous as possible as the MFT grows. The MFT area refers to the space reserved by the NTFS file system for MFT in each volume. File and directory space are also allocated from this space, but only after all volume space outside the MFT area has been allocated.

Depending on the average file size and other variables, when the disk is full, the reserved MFT area or unreserved space on the disk may be allocated first. Volumes with a small number of relatively large files will be allocated in unreserved space first, while volumes with a large number of relatively small files will be allocated in MFT area first.

In both cases, fragmentation of the MFT occurs when one area or another is fully allocated. If unreserved space is completely reserved, space for user files and directories will be allocated from the MFT area. If the MFT area is fully allocated, space for new MFT entries will be allocated from unreserved space.

Increase the Size of MFT

The MFT itself can be defragmented. You should reserve as much space as possible at the beginning of the MFT area before defragmenting the volume to reduce the chance that the MFT area is fully allocated before the defragmentation process is complete. If the MFT area is fully allocated before defragmentation is complete, there must be unallocated space outside the MFT area.

The default MFT area is calculated and retained by the system when the volume is mounted, and it is based on the size of the volume. You can increase the MFT zone, but you cannot make the default MFT zone smaller than what is calculated. Increasing the MFT area will not reduce the disk space that users can use for data files.

Master File Table Can Be Corrupted

Sometimes, the master file table can be corrupted. If the master file table gets corrupted, the files stored in the NTFS file system volume will be inaccessible. And when you try to access the drive, it will give error messages like “The parameter is incorrect” or “The file or directory is corrupted and unreadable”.

Well then, why the “corrupt master file table chkdsk aborted“ error would occur? Here are some reasons for the error. Let’s have a look together.

1. Sudden system crash like Windows Blue Screen of Death

2. Virus Attack or malware damage

3. Application malfunction

4. Improper removal of external disks

5. A lot of bad sectors on the hard drive

How to repair a corrupt master file table and recover data from the inaccessible partition? Now, read this post – Top 3 Fixes to Corrupt Master File Table (Solution 3 Saved Me!) to find the methods to fix it.

Final Words

To sum up, you have known the definition of MFT, the structure of it, and the methods to increase the size of it. In addition, you can know how to fix the corrupted MFT. I hope this post can be helpful to you.