How comes that short filenames (8.3) are created in one partition and not in another of the same disk?

Question

I run a 64-bit Windows 10 PC with a single hard disk with two NTFS partitions, C: and D:. Short filenames (8.3) are created in C: but not in D:

1. How is this possible, and
2. Can I enable short filenames in D: too?

Answer 1

The global setting for 8.3 name creation is controlled by the key HKLM\System\CurrentControlSet\Control\FileSystem\NtfsDisable8dot3NameCreation. The default value is 2 which means allowing each volume to have its own local 8.3 name creation setting. The available settings for that key are:

• 0: Enables 8dot3 name creation for all volumes on the system.
• 1: Disables 8dot3 name creation for all volumes on the system.
• 2: Sets 8dot3 name creation on a per volume basis.
• 3: Disables 8dot3 name creation for all volumes except the system volume.

When the value is 2, the setting for each volume can be get/set by the fsutil 8dot3name command

C:\WINDOWS\system32>fsutil 8dot3name query
The registry state is: 2 (Per volume setting - the default).

C:\WINDOWS\system32>fsutil 8dot3name query c:
The volume state is: 0 (8dot3 name creation is enabled).
The registry state is: 2 (Per volume setting - the default).

Based on the above settings, 8dot3 name creation is enabled on c:

How is this possible

The setting doesn't apply to all partitions in the whole system as said above. That means someone disabled 8.3 name creation in D:. With fsutil you can even add/remove 8.3 names for a specific file with fsutil file setshortname/fsutil 8dot3name strip regardless of the system/volume setting so another possible but less likely solution is that all the 8.3 names have been deleted and new files haven't been added to the volume

Since Windows 8 and Windows Server 2012 newly formatted volumes will have 8.3 name generation disabled by default. This is probably the situation in your PC

In fact, recent versions of Windows Server don’t even enable 8.3 naming when you format new data volumes.

https://docs.microsoft.com/en-us/archive/blogs/josebda/windows-server-2012-file-server-tip-disable-8-3-naming-and-strip-those-short-names-too

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Can I enable short filenames in D: too?

Yes, of course. To enable the setting on D: run

fsutil 8dot3name set D: 0

and to disable it

fsutil 8dot3name set D: 1

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Related:

• How to force short name (8dot3) generation?
• Create 8.3 name for an existing directory

Answer 2

Meanwhile, I found the right question to ask in Bing, which led me to the solution from http://omtool.com/documentation/HPCR/v1.2.0/ServerHelp/Enabling_8.3_name_creation.htm:

Go to HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\FileSystem in the registry and set NtfsDisable8dot3NameCreation to 0. (Default is 2). I tried it and it works.

But the first question still holds: How one partition has short names and the other not? The registry key applies to all NTFS file systems!

So, I don't delete my question for another also reason: other people might have the same question and cannot find the solution in the Web, as I couldn't myself.