Queries or sets the current file system behavior parameters, which include:


fsutil behavior query {disable8dot3 | allowextchar | disablelastaccess | quotanotify | memoryusage | mftzone}
fsutil behavior set [{disable8dot3 {1|0} | allowextchar {1|0} | disablelastaccess {1|0} | quotanotify <Frequency> | memoryusage <Value> | mftzone <Value>}]


Parameter Description


Queries the file system behavior parameters.


Changes the file system behavior parameters.

disable8dot3 {1|0}

Disables (1) or enables (0) the creation of 8.3 character-length file names on FAT- and NTFS-formatted volumes.

allowextchar {1|0}

Allows (1) or disallows (0) characters from the extended character set (including diacritic characters) to be used in 8.3 character-length short file names on NTFS volumes.

disablelastaccess {1|0}

Disables (1) or enables (0) updates to the Last Access Time stamp on each directory when directories are listed on an NTFS volume.

quotanotify <Frequency>

Configures how frequently NTFS quota violations are Frequency reported in the system log. Valid values for are in the range 0 – 4294967295. The default frequency is 3600 seconds (one hour).

memoryusage <Value>

Configures the internal cache levels of NTFS paged pool memory and NTFS non-paged pool memory. Set to 1 or 2. When set to 1 (the default), NTFS uses the default amount of paged pool memory. When set to 2, NTFS increases the size of its lookaside lists and memory thresholds. (A lookaside list is a pool of fixed-size kernel memory buffers that the kernel and device drivers create as private memory caches for file system operations, such as reading a file.)

mftzone <Value>

Sets the size of the MFT Zone, in increments of one-eighth the size of the disk. Set Value to a number from 1 (default) to 4 (maximum).


  • The MFT Zone is a reserved area that enables the MFT to expand as needed to prevent MFT fragmentation. If the average file size on the volume is 2 KB or less, it can be beneficial to set the mftzone value to 2. If the average file size on the volume is 1 KB or less, it can be beneficial to set the mftzone value to 4.

  • Because the behavior subcommand writes changes to the registry, you must restart the computer for these changes to take effect.

  • When disable8dot3 is set to 0, every time you create a file with a long file name, NTFS creates a second file entry that has an 8.3 character-length file name. When NTFS creates files in a directory, it must look up the 8.3 character-length file names that are associated with the long file names. This parameter updates the HKLM\SYSTEM\CurrentControlSet\Control\FileSystem\NtfsDisable8dot3NameCreation registry key.

  • The allowextchar parameter updates the HKLM\SYSTEM\CurrentControlSet\Control\FileSystem\NtfsAllowExtendedCharacterIn8dot3Name registry key.

    The disablelastaccess parameter reduces the impact of logging updates to the Last Access Time stamp on files and directories. Disabling the Last Access Time feature improves the speed of file and directory access. This parameter updates the HKLM\SYSTEM\CurrentControlSet\Control\FileSystem\NtfsDisableLastAccessUpdate registry key.


    • File-based Last Access Time queries are accurate even if all on-disk values are not current. NTFS returns the correct value on queries because the accurate value is stored in memory.

    • One hour is the maximum amount of time that NTFS defers updating Last Access Time on disk. If NTFS updates other file attributes such as Last Modify Time, and a Last Access Time update is pending, NTFS updates Last Access Time with the other updates without additional performance impact.

    • The disablelastaccess parameter can affect programs such as Backup and Remote Storage that rely on this feature.

  • Increasing physical memory does not always increase the amount of paged pool memory available to NTFS. Setting memoryusage to 2 raises the limit of paged pool memory. This might improve performance if your system is opening and closing many files in the same file set and is not already using large amounts of system memory for other applications or for cache memory. If your computer is already using large amounts of system memory for other applications or for cache memory, increasing the limit of NTFS paged and non-paged pool memory reduces the available pool memory for other processes. This might reduce overall system performance. This parameter updates the HKLM\SYSTEM\CurrentControlSet\Control\FileSystem\NtfsMemoryUsage registry key.

  • The Value value specified in the mftzone parameter is an approximation of the initial size of the MFT plus the MFT Zone on a new volume, and it is set at mount time for each file system. As space on the volume is used, NTFS adjusts the space reserved for future MFT growth. If the MFT Zone is already large, the full MFT Zone size is not reserved again. Because the MFT Zone is based on the contiguous range past the end of the MFT, it shrinks as the space is used.

    The file system does not redetermine the MFT Zone location until the current MFT Zone is completely used. Note that this never occurs on a typical system.

Additional references