What Is an MAS File?

Programs that can open an MAS file

What to Know

  • Some MAS files are Microsoft Access Stored Procedure Shortcut files.
  • Open one with MS Access.
  • Convert to a different format with that same program.

This article explains the different file formats that use the MAS file extension, plus how to open one and what your options are for converting an MAS file.

What Is an MAS File?

A file with the MAS file extension is most likely a Microsoft Access Stored Procedure Shortcut file. This format stores a query that has been pre-written and used by a Microsoft Access database.

MAS files that open with Microsoft Access

Another format that uses this file extension is rFactor Track, used by Image Space's rFactor racing simulation video game. It stores information about how the racing track should look. Additionally, some MAS files include other assets like vehicle and sound data and are sometimes seen alongside MFT files.

If not in either of these formats, your file might instead be a MEGA Alignment Sequence file that stores genetic information, in binary, for use with the MEGA software. This format is used to help align genetic codes between different samples.

How to Open an MAS File

Microsoft Access Stored Procedure Shortcut files open with Microsoft Access.

rFactor is the software that opens rFactor Track files. Some default MAS files are installed in the \rFactor2\Installed\ folder by default. Also available on the rFactor website is gMotor MAS File Utility, a portable program (you don't have to install it) that opens these kinds of files through its File > Open menu.

gMotor MAS File Utility is included in the "rFactor mod development tool pack" download, too, which you can also find on their download page. You can either download the whole pack or just the utility itself.

The software used to open MEGA Alignment Sequence files is called MEGA—use its Alignment Explorer tool via Align > Open Saved Alignment Session. This application might use the file to create other files, like MEGA Tree Session files (.MTS).

If these programs don't open your MAS file, you might want to try a text editor like Notepad in Windows, TextEdit in macOS, or some other free text editor program. When you view a file as a text document, you can often find a word or two that helps you identify the format it's in, which is often extremely helpful in finding an appropriate program that can open that particular file.

If you find that an application on your PC does try to open the file but it's the wrong application or you'd rather have another installed program open it, see how to change the default program for a specific file extension for making that change in Windows.

How to Convert an MAS File

It's unlikely that MAS files used with Access can be converted to another format, but you can try it to be sure. If it is possible, you'll be able to do so through the File > Save As menu.

If you're looking to convert an rFactor file, try looking through the menu for a File > Save As or Export option, which is usually how software programs convert file formats.

While MEGA is used to open some MAS files, it's unlikely that it can convert Alignment Sequence files—they seem to have a limited purpose and so probably aren't meant to exist in any other format. However, again, look in the menu for a conversion option.

Still Can't Open It?

A file that still won't open after trying the suggestions above may not be an MAS file. Be sure to double-check the file extension. There are definitely many examples of similarly spelled file extensions that are completely unrelated to MAS files, MAT and AMS being a couple.

If your file doesn't use the .MAS file extension, use the search box at the top of this page or go to Google, to learn more about the file extension to see what format the file is in and what program is able to open or convert it.

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