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MAS File - What is a .mas file and how do I open it?
Learn about .MAS files and view a list of programs that open them.
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Overview
What is a MAS file? A MAS file is a game data file for the rFactor racing simulation that stores all the assets for a racing track, including its geometry, textures, and other visual or structural components. MAS files allow the game to efficiently load and manage the track as a single package while keeping all related files organized.
More Information Developers and hobbyists who create or modify tracks for rFactor are most likely to encounter MAS files. They often extract or repack MAS files to add new features, textures, or layouts to existing tracks. While the MAS format supports custom track creation, editing and modding MAS files requires experience with the gMotor engine and related tools.
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DeveloperMicrosoft
Popularity2.0 | 3 Votes
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.MAS File Extension
3 file types use the .mas file extension.
rFactor Track File
| Developer | Image Space |
| Popularity |
3.9 | 11 Votes |
What is a MAS file?
A MAS file is a game data file for the rFactor racing simulation that stores all the assets for a racing track, including its geometry, textures, and other visual or structural components. MAS files allow the game to efficiently load and manage the track as a single package while keeping all related files organized.
More Information
Developers and hobbyists who create or modify tracks for rFactor are most likely to encounter MAS files. They often extract or repack MAS files to add new features, textures, or layouts to existing tracks. While the MAS format supports custom track creation, editing and modding MAS files requires experience with the gMotor engine and related tools.
How to open a MAS file
You can open MAS files using the gMotor MAS File Utility (MAS.EXE), which is discontinued. The utility lets you view, extract, or repack the contents of MAS files for editing or backup purposes.
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Programs that open or reference MAS files
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Image Space rFactor
Paid
gMotor MAS File Utility
—
Discontinued
Free
Category: Game Files
Updated: March 19, 2026
MEGA Alignment Sequence File
| Developer | MEGA Team |
| Popularity |
3.2 | 6 Votes |
A MAS file may also be a data file created by MEGA (Molecular Evolutionary Genetics Analysis), a program used to study evolutionary relationships between biological sequences. It stores a sequence alignment, such as a DNA, RNA, or protein sequence, along with information needed to maintain the alignment structure, in binary format.
More Information
The sequence alignments stored in MAS files help researchers, students, and bioinformaticians identify mutations, conserved regions, and evolutionary patterns. The stored alignments can also serve as input for additional analyses, such as building phylogenetic trees ( .MTS files) or calculating evolutionary distances.
How to open a MAS file
You can open MAS files with MEGA. Once opened, you can view and edit the aligned sequences or use the data for downstream analyses within the software.
Programs that open MAS files
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MEGA
Free
Mac
MEGA
Free
Category: Data Files
Updated: March 19, 2026
Access Stored Procedure
| Developer | Microsoft |
| Popularity |
2.0 | 3 Votes |
A MAS file may also be a stored procedure created and used by Microsoft Access . It contains functions used to retrieve and/or modify data stored in an Access database. MAS files consist of field names and SQL statements used to retrieve or modify data stored in those fields.
More Information
Stored procedures are pre-written, embedded database commands that allow applications connected to a relational database management system, such as Access, to perform common functions without including those functions in their own code. This allows developers to streamline their application code, by referencing the stored procedure in one or more apps' code, rather than writing it out each time it is needed.
In most cases, Access saves stored procedures within the database with which they are used, and not as separate files. However, on occasion, you may see Access stored procedures saved as MAS files.
How to open a MAS file
You can use Microsoft Access to execute the procedure a MAS file contains (provided you have access to a compatible database).
Programs that open MAS files
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Microsoft Access 365
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Category: Database Files
Updated: July 19, 2023