--- title: "NtfsDisableLastAccessUpdate and NtfsDisable8dot3NameCreation: what they change" description: "NTFS can record when each file was last read and keep a short DOS-style name (PROGRA~1) for every file. What it changes, when it hurts, and how to undo it." url: https://frozentweaks.com/tweaks/ntfs-last-access-and-8dot3-names author: Frost LIVE, Founder of Frozen Tweaks published: 2026-10-08 updated: 2026-10-08 category: "Clean" source: Frozen Tweaks (https://frozentweaks.com) --- # NtfsDisableLastAccessUpdate and NtfsDisable8dot3NameCreation: what they change **Short answer:** NTFS can record when each file was last read and keep a short DOS-style name (PROGRA~1) for every file. Both cost a little work on every file operation. This tweak turns last access updates off and stops new short names from being created. In the registry it sets NtfsDisableLastAccessUpdate to 1 under HKLM\SYSTEM\CurrentControlSet\Control\FileSystem, and 1 more value. ## In the app - Switch: NTFS Lean FS (Clean, Pro, Advanced) - Undo: Partial. Switching it off turns last-access time updates on for every drive. Windows ships this set to system managed, where Windows decides per drive. - Catalog row: https://frozentweaks.com/tweaks#t-1070 ## What it does NTFS can record when each file was last read and keep a short DOS-style name (PROGRA~1) for every file. Both cost a little work on every file operation. This tweak turns last access updates off and stops new short names from being created. In the app the switch is called "NTFS Lean FS", described there as: Disables LastAccess & 8.3 names to cut FS metadata overhead. ## When it helps - Folders with very many files, where creating and listing files gets slightly faster. ## When it hurts - Very old installers and 16-bit era programs that depend on short names can fail. - Tools that rely on 'last accessed' dates, including some backup and cleanup tools, lose that information. Existing short names are kept. ## What it writes Read from the app's source. "Switching it off" is what the app writes when you turn the tweak off again. Registry values: | Key | Value | With the tweak | Switching it off | | --- | --- | --- | --- | | `HKLM\SYSTEM\CurrentControlSet\Control\FileSystem` | `NtfsDisableLastAccessUpdate` | `1` | 0 | | `HKLM\SYSTEM\CurrentControlSet\Control\FileSystem` | `NtfsDisable8dot3NameCreation` | `1` | 2 | Source: Tweaks/ntfs_fs_lean.hpp in the app's source, app 2.0.0, checked 2026-10-08. ## The same change by hand Run in a Command Prompt opened as administrator. Make a restore point first. ```bat reg add "HKLM\SYSTEM\CurrentControlSet\Control\FileSystem" /v "NtfsDisableLastAccessUpdate" /t REG_DWORD /d 1 /f reg add "HKLM\SYSTEM\CurrentControlSet\Control\FileSystem" /v "NtfsDisable8dot3NameCreation" /t REG_DWORD /d 1 /f ``` Put it back: ```bat reg add "HKLM\SYSTEM\CurrentControlSet\Control\FileSystem" /v "NtfsDisableLastAccessUpdate" /t REG_DWORD /d 0 /f reg add "HKLM\SYSTEM\CurrentControlSet\Control\FileSystem" /v "NtfsDisable8dot3NameCreation" /t REG_DWORD /d 2 /f ``` See what it is set to now: ```bat reg query "HKLM\SYSTEM\CurrentControlSet\Control\FileSystem" /v "NtfsDisableLastAccessUpdate" ``` ## How to undo it Switch the tweak off in Frozen Tweaks. It writes NtfsDisableLastAccessUpdate back to 0, NtfsDisable8dot3NameCreation back to 2. Switching it off turns last-access time updates on for every drive. Windows ships this set to system managed, where Windows decides per drive. ## Verdict A small, real saving on file-heavy work. Modern Windows already avoids most last access updates on large drives. ## Questions ### What does the "NTFS Lean FS" tweak change in Windows? In the registry it sets NtfsDisableLastAccessUpdate to 1 under HKLM\SYSTEM\CurrentControlSet\Control\FileSystem, and 1 more value. The full list is in the table on this page, read from the app's source. ### What is the standard value of NtfsDisableLastAccessUpdate? Frozen Tweaks writes 0 when you switch the tweak off, which is the value it treats as the Windows standard. With the tweak on, NtfsDisableLastAccessUpdate is 1. ### Is "NTFS Lean FS" safe to switch on? A small, real saving on file-heavy work. Modern Windows already avoids most last access updates on large drives. The main cost: Very old installers and 16-bit era programs that depend on short names can fail. ### How do I undo it? Switch the tweak off in Frozen Tweaks. Switching it off turns last-access time updates on for every drive. Windows ships this set to system managed, where Windows decides per drive. ### Is "NTFS Lean FS" free in Frozen Tweaks? It is part of Frozen Pro and Elite. You can also make the change by hand with the values on this page. ## Related guides - [Windows 11 Gaming Optimization: What Still Works in 2026](https://frozentweaks.com/guides/windows-11-gaming-optimization) - [What Is Safe to Delete on a Gaming PC, and What to Leave Alone](https://frozentweaks.com/guides/what-to-delete-on-a-gaming-pc) ## More tweak explainers - [EnablePrefetcher and EnableSuperfetch](https://frozentweaks.com/tweaks/enableprefetcher-and-enablesuperfetch) - [Distributed Link Tracking Client (TrkWks)](https://frozentweaks.com/tweaks/disable-distributed-link-tracking) - [Scheduled drive optimization](https://frozentweaks.com/tweaks/disable-scheduled-defrag-and-trim) --- Written by Frost LIVE, founder of Frozen Tweaks. Canonical version: https://frozentweaks.com/tweaks/ntfs-last-access-and-8dot3-names