Satisfactory uses a consistent LocalAppData SaveGames root across Steam and Epic, but the account-ID directory underneath is important: a player who switched storefronts can have more than one valid subfolder. SaveEditor recommends comparing timestamps and preserving all relevant .sav generations rather than uploading or editing the first file found. This is also a format-version-sensitive game, so an external calculator saying “unsupported save version” can simply mean that tool has not caught up with a new game build.
Known Satisfactory save-file structure
The researched filename or folder pattern is *.sav files; the filename normally reflects the save/session name, with multiple autosave/manual versions possible.. File-extension context: .sav The documented format notes are: Steam and Epic use the same SaveGames root but place saves in account-ID subfolders. The game format changes across builds, so external tools may lag behind the current save version.
Why an extension is not enough
A save filename can identify a likely container, but it does not prove the internal schema, game version, checksum rules, encryption state, or editability. A third-party tool rejecting a .sav can mean the tool has not yet added the current Satisfactory save version; it does not prove the game file itself is corrupt. SaveEditor therefore separates file identification from Tool compatibility and only labels a game-specific Tool Verified when its exact profile/version evidence passes the runtime gate.
Where the format is stored
PC save locations: Windows: %LOCALAPPDATA%FactoryGameSavedSaveGames<account-id>. Storefront context: Steam, Epic Games Launcher. Steam and Epic can create different account-ID subfolders under the same root. Selecting the wrong folder can make the correct .sav look missing. This matters because two releases can use different containers or companion files even when the visible slot name is similar.
Back up before inspecting or editing
Back up the complete account-ID folder, not just the latest autosave. Keep several generations before moving between Early Access/Experimental/current builds or using an external calculator/editor. A read-only viewer is lower risk than a writer, but the live save should still be copied first. Cloud context also matters: Steam Cloud and Epic cloud are documented. Cloud conflicts are especially relevant when switching machines or branches. Keep the original bytes available so any experiment can be reversed without relying on a cloud service or automatic backup.
What this reference does not claim
This page does not infer an undocumented checksum algorithm, encryption key, compression layer, or cross-store conversion from the file extension. Troubleshooting evidence: If the expected .sav is absent, look one level below SaveGames for all account-ID folders and compare timestamps. If an external parser rejects it, test the save in the game before diagnosing damage. Those questions require a verified parser/profile or a game-specific source, not a generic format guess.
Verification context: Reviewed against current PCGamingWiki and Official Satisfactory Wiki save-file documentation, including the account-ID subfolder and current cloud-conflict guidance.