NieR: Automata is a case where backing up only “the save slot” can miss important surrounding state. Steam exposes three SlotData files but also stores GameData and SystemData in the same Documents directory. Ending and presentation state can therefore outlive a single slot replacement. SaveEditor recommends treating the folder as one backup set, then making any slot-level experiment only on a copy. Microsoft Store is additionally separated by its WGS container, so its files should not be treated as Steam .dat files solely because the gameplay is the same.
Known NieR: Automata save-file structure
The researched filename or folder pattern is Steam: SlotData_0.dat, SlotData_1.dat, SlotData_2.dat plus GameData.dat and SystemData.dat.. File-extension context: .dat The documented format notes are: Steam stores three slot files alongside broader game/system data. Microsoft Store wraps saves in WGS containers. A slot file alone does not necessarily represent every piece of progression or presentation state.
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. Ending-related and global progression can involve GameData in addition to SlotData. Do not assume one slot file is the only state worth preserving. 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: Steam: %USERPROFILE%DocumentsMy GamesNieR_Automata ; Microsoft Store: %LOCALAPPDATA%Packages39EA002F.NieRAutomataPC_n746a19ndrrjgSystemAppDatawgs. Storefront context: Steam, Microsoft Store. Steam and Microsoft Store use different containers; cross-store transfers may require renaming and account/ID-aware handling rather than a raw overwrite. 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 NieR_Automata folder on Steam, including SlotData, GameData, and SystemData, before replacing one slot. Preserve the full WGS tree on Microsoft Store. 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 Xbox Cloud can restore saves for their storefronts. 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 slot vanishes or fails to load, verify the exact SlotData index, Steam account, cloud-conflict choice, and whether broader GameData/SystemData came from the same backup set. Those questions require a verified parser/profile or a game-specific source, not a generic format guess.
Verification context: Reviewed against current PCGamingWiki NieR: Automata save paths and slot-transfer notes plus current community descriptions of SlotData/GameData/SystemData.