Windows 11 still carries a legacy of the MS-DOS era: the "8.3" short file name format.
For example, a folder with a long name can automatically be given a separate short name such as PROGRA~1. The feature exists to maintain compatibility with old software, but Microsoft also provides a setting that stops Windows from creating these short names for performance reasons.
There is an important distinction, however. Stopping Windows from creating short names going forward is not the same as deleting short names that already exist.
Microsoft specifically warns about the latter: removing existing short names can cause apps to stop working correctly or become impossible to uninstall.
Disabling 8.3 names also does not speed up Windows 11 as a whole. The large performance difference Dell observed occurred under a very specific condition: continuously creating more than a million files in a single folder.
So rather than treating this setting as a general "Windows speed-up trick," it makes more sense to consider separately which workloads it helps and where the compatibility risks lie.
"Stop creating new short names" vs. "delete existing short names"
Microsoft's fsutil 8dot3name command offers several operations for handling 8.3 short names.
query checks the current setting.
set changes whether 8.3 short names are assigned to files and folders created from now on.
strip, on the other hand, removes short names already attached to existing files and folders.
This difference matters.
| Operation | What it does | Caution |
|---|---|---|
query |
Checks the current 8.3 setting | Does not change any settings |
set |
Changes whether new short names are created going forward | Watch for compatibility with software that relies on old short names |
scan |
Looks for registry entries likely to be affected if short names are removed | Does not automatically fix any references it finds |
strip |
Deletes short names that already exist | May cause apps to malfunction or become impossible to uninstall |
The operation Microsoft warns about most strongly is strip, which deletes existing short names.
Some software records short paths such as PROGRA~1 in the registry or elsewhere at install time.
If that short name is later removed, the software ends up referring to a path that no longer exists.
Running strip also does not automatically rewrite old paths stored in the registry.
The /f option forces the removal even when such references are found. That is why Microsoft recommends backing up before running it and explicitly notes that apps may stop working or become impossible to uninstall.
By contrast, stopping the creation of new short names with set leaves existing short names in place.
In other words,
- reducing the overhead of creating short names from now on
- deleting short names created in the past
are two different changes, both in terms of performance and compatibility.
Why does an MS-DOS-era mechanism still exist in Windows 11?
The name "8.3" comes from a file-name limitation in old DOS.
The format allowed up to 8 characters for the file name and up to 3 for the extension.
Modern Windows handles long file names without trouble, but to stay compatible with old software, it can maintain a short name alongside the long one.
For example, a folder named
Program Files
can also have the short name
PROGRA~1
This does not create a second folder. Either name gives access to the same folder.
Some older software cannot handle long file names correctly, so these short names have been kept for compatibility.
In environments that use only modern software, though, it may not be necessary to create short names for every file.
That is why Microsoft allows 8.3 short name creation to be disabled for performance reasons.
According to Microsoft's NTFS overview, short name creation is disabled by default on some newly formatted volumes in recent versions of Windows.
However, on the system volume where Windows is installed, it may remain enabled to preserve software compatibility.
So while Microsoft itself does not consider the feature necessary on every drive, it treats it as something that cannot easily be turned off in places used by Windows and existing software.
Major slowdown with more than a million files
One example of 8.3 names affecting performance is an investigation published by Dell Technologies.
Dell looked into a problem in its Avamar backup product in which restoring a folder containing more than a million files did not finish even after days.
According to Dell's published findings, file creation slowed dramatically on NTFS volumes with 8.3 short names enabled.
To isolate the cause from Avamar's own processing, Dell ran a test that continuously created a large number of differently named files in a single directory.
It compared the number of files created per unit of time with 8.3 names enabled and disabled.
With 8.3 enabled, file creation slowed markedly starting at around 1.3 million files.
With it disabled, more than 5 million files were created in two to three hours.
Dell gives roughly 1.1 million files as the point at which the practical slowdown becomes noticeable.
That does not mean NTFS itself has a limit of 1.1 million files.
Dell also says the file count at which the slowdown begins varies with hardware and environment.
In other words, 1.1 million and 1.3 million are not universal Windows thresholds but rough figures Dell observed in a particular environment.
Ordinary Windows operations don't get faster
It would be wrong to read this result as "disabling 8.3 makes Windows dramatically faster."
What Dell measured was continuously creating a huge number of files in a single directory.
It was not a test of game frame rates, app launch times, SSD read/write speeds, or how quickly File Explorer opens an ordinary folder.
So on an ordinary Windows PC, turning off 8.3 will not necessarily produce a noticeable speedup.
The impact is most likely in workloads that create very large numbers of files in one folder.
When 8.3 is enabled, Windows has to manage a corresponding short name in addition to the long file name.
When the file count grows extremely large, generating and managing those short names becomes extra load.
For that reason, it may be worth considering in environments such as:
- Volumes where large numbers of files are restored from backups
- Areas that store large volumes of build artifacts
- Storage handling very many small data files
- Systems that generate large numbers of log files
That said, what Dell actually measured was mass file creation tied to Avamar restores.
The test does not prove that build or log storage would see the same degree of improvement.
What matters is not only the total number of files, but also:
- how heavily they are concentrated in a single directory
- which software uses that area
- whether that software depends on 8.3 short names
If you disable it, limit the scope rather than changing the whole PC
Windows offers settings from 0 to 3 for controlling 8.3 short name creation.
Broadly speaking, they allow you to choose between:
- enabled on all volumes
- disabled on all volumes
- configured per volume
- enabled only on the system volume
That makes it possible, for example, to keep short names on the C: drive where Windows is installed to preserve compatibility, while not creating them on a separate drive that stores large amounts of data.
This shows that Microsoft does not treat 8.3 as a simple on/off feature.
You can change the setting only for the specific volume where performance problems occur and leave it in place where compatibility is needed.
If you also want to delete existing short names, further careful checking is required.
You can use scan to look for registry entries that could be affected by the removal.
With strip /t, you can see which short names would be targeted for removal without actually deleting them.
However, finding no problems with these commands does not guarantee complete safety.
scan mainly checks references in the registry, and it may not catch every other place where short paths are used, such as an app's internal configuration files or scripts.
For that reason, changing 8.3 settings should not be thought of as a "Windows speed-up switch" for general users.
The first thing to check is not whether the PC feels slow overall, but whether a specific directory is receiving an extreme number of files.
Then confirm that the software using that location does not depend on 8.3 short names, and if necessary, stop new short name creation only on the data volume.
What Dell's case shows is not a trick for speeding up ordinary Windows 11, but that in special environments handling files on the scale of more than a million, an old compatibility feature can impose a significant processing burden.