Elden Ring concentrates multiple characters in a single profile-level .sl2 container, so the practical backup unit is the whole account folder, not one character slot. The nearby .bak file is useful as a possible recovery point but should itself be backed up before experimentation. Because Steam Cloud can synchronize the same profile, restoration should be deliberate: close the game, preserve current local files, decide which copy is authoritative, then allow cloud sync to resume.
Known Elden Ring save-file structure
The researched filename or folder pattern is ER0000.sl2
ER0000.sl2.bak. File-extension context: .sl2, .bak The documented format notes are: The Steam PC profile uses an account-ID folder and the main ER0000.sl2 container. The .bak companion can provide an additional recovery point, but it should be copied before trying to restore it.
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. Save files can contain multiple characters and account-specific data. Do not treat an individual character as a standalone file. 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: %APPDATA%EldenRing<user-id> | Linux / Steam Play: Steam Play: <SteamLibrary-folder>/steamapps/compatdata/1245620/pfx/. Storefront context: Steam. The account-ID subfolder is part of the save context. Avoid mixing files between Steam identities without a tool explicitly designed for that purpose. 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
Copy ER0000.sl2 and its .bak companion with the game closed. For maximum safety, copy the entire account-ID folder to a dated backup outside AppData. 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 is documented. 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 a manual restore is immediately replaced, pause and inspect Steam Cloud synchronization instead of repeatedly overwriting the live folder. Preserve both local and cloud versions until you know which one is newer. Those questions require a verified parser/profile or a game-specific source, not a generic format guess.
Verification context: Windows/Steam Play path and Steam Cloud support were reviewed against current PCGamingWiki coverage. Filename notes reflect the standard Steam PC profile layout.