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.
Start with the least destructive explanation
When Elden Ring progress appears missing, first verify the active PC location: Windows: %APPDATA%EldenRing<user-id> | Linux / Steam Play: Steam Play: <SteamLibrary-folder>/steamapps/compatdata/1245620/pfx/. Expected files/folders: ER0000.sl2
ER0000.sl2.bak. Many apparent save failures are actually profile, storefront, path-redirection, or cloud-selection problems rather than damaged game data.
Preserve every surviving copy
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. Before renaming, moving, replacing, or opening candidate backups, copy them outside the live directory. Do not use the only surviving file as the test specimen for repair or editing.
Check launcher and cloud state
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. Cloud notes: Steam Cloud is documented. A sync client can reintroduce an older or newer version after a manual restore, so recovery work should keep local and cloud copies conceptually separate until the wanted progress is confirmed.
Use format and compatibility clues
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. Save files can contain multiple characters and account-specific data. Do not treat an individual character as a standalone file. If the file exists but is ignored, compare the complete directory structure, slot/profile naming, game edition, mods/DLC, and any companion metadata. Do not assume an extension change or generic checksum tool can repair a game-specific container.
Game-specific troubleshooting
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. If a known-good backup works, preserve it and create a fresh in-game save before further experiments. If no copy works, prefer read-only inspection and source-backed game-specific tooling over repeated writes.
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.