ALS File

What are ALS files and how to open them

Are you having problems opening an ALS 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 ALS files.

What is an ALS file?

ALS files have multiple uses, and Calmira Alias is one of them. Read more about the other uses further down the page.

Calmira Alias

Calmira Alias files serve as shortcut objects created by the shell environment known as Calmira, a 16-bit shell replacement for Windows 3.1. These alias files do not hold full copies of the items they reference; instead, they point to other files, folders, or objects so that users can launch or access them quickly from another location in the Calmira desktop or menus. They are used when you create an alias (or shortcut) in Calmira's interface, such as dragging an icon to the desktop or adding a menu item in Calmira's UI.

These files are written by Calmira itself and read by Calmira when managing or launching the linked objects. When Calmira starts up or when its desktop or menu system is used, it looks into the alias files to determine what each alias points to and how it should behave (for example, what icon to display, what target path to call, etc.).

As an internal identifier, these files begin with the ASCII header .CMSR located at byte offset 0x0. That signature marks them as Calmira alias files, distinguishing them from other file types.

If you have such a file on your system, it likely appears because you created a shortcut (alias) in Calmira. To use or delete it, Calmira must be installed (or active as the shell); the alias files will then be recognized and handled automatically.

How to open ALS files

Important: Different programs may use files with the ALS file extension for different purposes, so unless you are sure which format your ALS 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 ALS openers which you will find listed below.

Last updated: August 17, 2026

All known file formats using extension .ALS

While Calmira Alias is a popular type of ALS-file, we know of 3 different uses of the .ALS file extension. Different software may use files with the same extension for different types of data.

MPEG-4 ALS (Audio Lossless coding Standard)

These ALS files contain audio in Audio Lossless Coding Standard format, which is a part of the MPEG-4 Part 3 standard. These ALS files combine short and long-term predictors to improve the compression for sound with rich harmonics.

Psion Serie 3 Application Alias

A Psion Serie 3 Application Alias file makes it possible to show a different icon and list under the System Screen for an existing application, so that the same program can appear multiple times under different names or behave slightly differently depending on how it's launched. It is a helper file used by the Psion Series 3 family (especially the 3a, 3c, and Siena) to alias an application already present in the system. When you install or create an alias, it appears on the System Screen like a separate app, though under the hood it refers back to the original application.

Such alias files are created by users via the "Create new list" command in the Special menu on the Series 3a/c and Siena, or by developers constructing aliases for long file lists (for example, to split one application's files into multiple separate lists). The alias file defines the public name that appears under the icon, the default file extension, the default directory, the type number of the application, and crucially it specifies which program is being aliased. Optionally it also embeds extra alias information (arguments) that the System Screen passes via the command line to alter behaviour when the application is run.

Internally the alias file is produced via a tool called makeals that combines two files with the same base name - one .ma file (alias metadata) and one .pic file (icon) - to build the .als file. Its file header begins with the ASCII signature "AppAliasFile***" starting at byte offset 0, which helps software identify it as this Psion Application Alias format.

Various apps that use files with this extension

These apps are known to open certain types of ALS files. Remember, different programs may use ALS 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 ALS file formats, example files, or compatible programs. Please use the links below or email us at submit@file.org to discuss further.