Ax Application File Extence

Application file extensions

Dynamics AX uses a lot of file extensions, but luckily, there is logic to them, so you can easily identify their purpose.

Most of these files are located in the application folder (AX 2009):
C:\Program Files\Microsoft Dynamics AX\50\Application\Appl\ [your_application]

The extensions have 3 characters:
The first character indicates the owner of the file:

a: application
k: kernel

The second character indicates the content of the file:

l: label
o: object
t: text
d: developer documentation
h: help

And the third character indicates the type of file:

d: data
i: index
c: cache
t: temporary

Using this logic, we can easily name all file extensions, and understand their purpose.

In the application folder:
ALD extension: Application Label Data files
These files contain the labels and label comments for a specific language of a label file.

ALC extension: Application Label Cache files.
These files contain the application label cache. These files can be deleted when the AOS is stopped.

ALI extension: Application Label Index files.
The .ali files contain an index to the .ald files. These files can be deleted when the AOS is stopped.

ALT extension: Application Label Temporary files.
These files contain new labels before they are committed to the .ald file.

AOI extension: Application Object Index file
The AOI file contains an index to the AOD files. You can delete this file when the AOS is stopped. Be sure to delete this when you have copied layers from one AX installation to another.

ADD extension: Application Developer Documentation Data files.
These files contain the documentation that is found under the Application Developer Documentation node. These files are localized, just like label files.

ADI extension: Application Developer Documentation Index files.
This is the index to the ADD file.

AHD extension: Application Help Data files
The AHD file contains the documentation aimed at the end user. In the AOT, this is found in the “Application Documentation” node.

AHI extension: Application Help Index files.
This is the index to the AHD file.

AOD extension: Application Object Data file.
This is the ‘AX layer file’; each of these files represents one layer.

KHD extension: Kernel Help Documentation files.
These files contain the kernel help documentation you can find in the AOT in the tree node System Documentation.

KHI extension: Kernel Help Index files

The KHI file is the index to the Kernel Help file.

Located in Server/bin:
KTD extension: Kernel Text Data file.
This file contains system text strings. These are used in the interface of AX and for system messages.

KTI extension: Kernel Text Index file.
This is the index to the KTD file.