.FOS File Extension

Fallout Save

Developer Bethesda Softworks
3.4  |  5 Votes

What is a FOS file?

A FOS file is a saved game created by Fallout 3, Fallout: New Vegas, or Fallout 4. It contains a record of a player's game progress, saved in a proprietary file format. All saves created by Fallout 3, New Vegas, and 4, including manual, quick, and autosaves, are saved as FOS files.

More Information

In the Fallout series, players explore a post-apocalyptic world that has been devastated by nuclear war. Fallout 3 was the first Fallout game to feature 3D graphics and real-time (rather than turn-based) combat. It was followed by Fallout: New Vegas and Fallout 4.

All three of these games store players' saved games as FOS files. In Windows, players can view their FOS files at the following locations:

  • Fallout 3: C:/​Users/​YourUserName/​Documents/​My Games/​Fallout3/​Saves
  • Fallout: New Vegas: C:/​Users/​YourUserName/​Documents/​My Games/​FalloutNV/​Saves
  • Fallout 4: C:/​Users/​YourUserName/​Documents/​My Games/​Fallout4/​Saves

If a player accumulates a large number of FOS files, the files' size may cause Fallout to lag when displaying some menus. Players can fix this issue by moving old FOS files out of their Saves folder.

How to open a FOS file

To use a FOS file with its corresponding Fallout game, place the file in that game's Saves directory. (The locations of Fallout 3, New Vegas, and 4's Saves directories are noted above.) Then, load the saved game your FOS file contains from within Fallout 3, New Vegas, or 4.

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Programs that open or reference FOS files

Verified by FileInfo.com

The FileInfo.com team has independently researched the Fallout Save file format and Windows apps listed on this page. Our goal is 100% accuracy and we only publish information about file types that we have verified.

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