Open FOS files in your browser
The save of Fallout 4. Open one right here to see who it is, where they are and the mods it needs, without the game. Nothing leaves your device.
Or drop it anywhere on this page
What you'll see
Your file opens on a page of its own, with what it holds in plain words.
- What it holds • In plain words, from the file itself
- What's locked • Said plainly, never decrypted
- Nothing in it runs
- Read, never changed
About FOS
Fallout 4 saves each game as a .fos file in Documents\My Games\Fallout4\Saves, its name made of the save's number, the character and the place, with an .f4se file beside it when the Script Extender is installed.
A .fos starts with FO4_SAVEGAME and a header of what the load menu shows: the character's name, level and sex, where they are, the in-game time, when it was saved and a screenshot in RGBA. Then come the version of the game that saved it, the plugins it was played with, light plugins (.esl) apart, and the state of the world.
Filepeek reads the header, the screenshot, the game's version and the plugin list, so you can see which mods a save needs before you load it. The state of the world isn't shown.
Fallout 4 save
.fos
Format
- MIME type
- application/octet-stream
- Made by
- Bethesda Game Studios
- Released
- 2015
Inside the file
- Header
- Name, level and location
- Screenshot
- RGBA
- Game version
- Like 1.10.163.0
- Plugins
- Masters, mods and light plugins
Opens in every browser
Filepeek reads a FOS in Chrome, Edge, Firefox and Safari. On their own, browsers only download it.
- YouChromeOpens through Filepeek
- YouEdgeOpens through Filepeek
- YouFirefoxOpens through Filepeek
- YouSafariOpens through Filepeek
Apps that open FOS
- WindowsFallout 4 loads it • FallrimTools' ReSaver reads it
- MacNo app opens it
- iPhone and iPadNo app opens it
- AndroidNo app opens it
Questions
How do I see which mods a Fallout 4 save needs?
Drop the .fos on this page or choose Peek a FOS. Its page lists every plugin the save was played with, masters first, then mods and light plugins, so you can match your load order before you load it.
Which version of Fallout 4 made a save?
Its page shows the version the save keeps after its screenshot, like 1.10.163.0, so you can tell a save from before the next-gen update from one made after it.
Why does the game warn about missing content?
A plugin the save was played with isn't active anymore. Its page here names each plugin the save expects, so you can find the one that's missing.
Can it edit a save?
No. Filepeek only reads it, and the file stays as it was.