AML File

What are AML files and how to open them

Are you having problems opening an AML file or are you simply curious about its contents? We're here to explain the properties of these files and provide you with software that can open or handle your AML files.

What is an AML file?

AML files have multiple uses, and Abstract Markup Language is one of them. Read more about the other uses further down the page.

Abstract Markup Language

These AML files are developer files that contain the code used to create documents or websites. AML is a markup language similar to XML or HTML, but it is more generic and used to write documents that need to be output in multiple formats, e.g., as an HTML page and a WML document.

How to open AML files

Important: Different programs may use files with the AML file extension for different purposes, so unless you are sure which format your AML file is, you may need to try a few different programs.

While we have not verified the apps ourselves yet, our users have suggested ten different AML openers which you will find listed below.

Last updated: August 18, 2026

All known file formats using extension .AML

While Abstract Markup Language is a popular type of AML-file, we know of 4 different uses of the .AML file extension. Different software may use files with the same extension for different types of data.

ACPI Machine Language

ACPI Machine Language is a low-level bytecode language defined by the Advanced Configuration and Power Interface standard. Firmware vendors write device descriptions and control methods in ACPI Source Language, which are compiled into this format. The operating system loads these AML images from ACPI tables to build its internal representation of hardware, then uses an AML interpreter to execute the AML‐encoded methods for tasks like power management, device configuration, and event handling.

Patterned as a virtual machine language, AML is made up of definition blocks that contain named objects, data, and executable methods. These blocks (such as DSDT and SSDT tables) are stored by firmware and loaded by the OS during initialization. AML is strictly bytecode - each operation, declaration, conditional, or loop is encoded in fixed and variable‐length byte sequences defined in the ACPI specification; tools like ASL compilers translate human‐readable ASL into binary AML form.

Files in this format begin with a table header (DefBlockHeader) that includes a TableSignature, TableLength, OEM identifier fields, checksum etc. After the header, the AML byte stream encodes Name objects, Data objects, Term objects and more, using encodings for constants (BytePrefix, WordPrefix, StringPrefix, etc.), package lengths (PkgLength encodings with 1 to 4 bytes), and opcodes for control-flow and namespace operations.

Microsoft Assistance Markup Language

This AML file is an XML-based markup language created by the Microsoft User Assistance Platform, a Microsoft platform designed to provide user assistance on Windows Vista Operating System. This AML file focuses more on the content and tasks performed with a computer. Microsoft AML files focus on different types of content like FAQ, glossary, procedure, reference, tasks, etc.

Morpheus Layout - Project

We know that one AML format is Morpheus Layout - Project. We have not yet analyzed in detail what these files contain and what they are used for. We're working on it.

Various apps that use files with this extension

These apps are known to open certain types of AML files. Remember, different programs may use AML files for different purposes, so you may need to try out a few of them to be able to open your specific file.

Help us help others

File.org helps thousands of users every day, and we would love to hear from you if you have additional information about AML file formats, example files, or compatible programs. Please use the links below or email us at submit@file.org to discuss further.