Elder Scrolls or Fallout 4 Master File
4.2 | 18 Votes
What is an ESM file?
An ESM file is a game data file used by select Bethesda Softworks video games, such as The Elder Scrolls IV: Oblivion, The Elder Scrolls V: Skyrim, or Fallout 4. It contains multiple records that describe various kinds of game data, such as characters, in-game items, world environments, and settings.
Bethesda introduced the ESM file type as part of 2002's The Elder Scrolls III: Morrowind. Various Bethesda games contain ESM files, as do official expansion packs and unofficial plug-ins created and distributed by game modders. (Modders also use .ESP files to modify Elder Scrolls IV, Elder Scrolls V, and Fallout 4.)
You can find ESM files in the Data sub-directory of a game's parent directory (the directory in which the game's .EXE file is located). For example, Elder Scrolls IV: Oblivion's primary ESM file, which is named Oblivion.esm, is located in the game's /Oblivion/Data folder.
NOTE: The .ESL file type is a "lighter" version of the ESM file type. It was introduced with the Fallout 4 patch 1.10 in August 2017 and is limited to 4096 records.
How to open an ESM file
Bethesda Softworks games that use ESM files automatically load and use the files when you play the games.
You can also view and edit custom ESM files with the Creation Kit or The Elder Scrolls Construction Set (TESCS) in Windows.
Programs that open or reference ESM files
Fallout 3 Master File
3.8 | 5 Votes
Game data file used by the Fallout 3, a single-player post-nuclear fallout role-playing game; contains core data that is loaded when the game is run; includes maps, object data, object placement locations, character dialogue, gameplay settings, AI settings, and other information.
ESM files are not meant to be edited, but may be modded using a tool like The Garden of Eden Creation Kit (GECK). By altering files, such as the Fallout3.esm file included with Fallout 3, players can modify the gameplay.
NOTE: While ESM files are sometimes altered to create custom game mods, the .ESP format can be used for plugins.