Monster Hunter: World keeps its main Steam PC progress in SAVEDATA1000. Because the file sits under an account-specific Steam userdata tree, the account context belongs in the backup record. Copy the file outside Steam before major changes and keep multiple dated revisions rather than relying on cloud synchronization alone. A future editor must handle account/profile semantics explicitly; Phase 23 only documents where the file lives and how to preserve it safely.
Known Monster Hunter: World save-file structure
The researched filename or folder pattern is SAVEDATA1000. File-extension context: No single extension is sufficient to identify every relevant save record. The documented format notes are: The Steam PC profile uses the SAVEDATA1000 file under app 582010 remote storage. The file contains account/profile progress and should be treated as user-associated data rather than an anonymous portable save.
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. Third-party save transfers often need Steam-ID-aware handling. This Game Hub does not claim that a SAVEDATA1000 file from another account is directly portable. 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-folder>userdata<user-id>582010remote | Linux / Steam Play: Steam Play: <SteamLibrary-folder>/steamapps/compatdata/582010/pfx/. Storefront context: Steam. The save is under Steam userdata, not the Monster Hunter: World installation directory. The numeric user folder identifies the Steam account context. 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 SAVEDATA1000 to a dated location outside Steam userdata. For extra context, record the Steam account/ID that produced the file. 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/remote storage is part of the normal PC workflow. Manual backups are still valuable because a damaged local revision can also synchronize. 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 progress is missing after a cloud conflict, preserve both the current remote/local file and any backup before trying replacement. Avoid repeatedly launching the game while deciding which copy is authoritative. Those questions require a verified parser/profile or a game-specific source, not a generic format guess.
Verification context: The Steam userdata path was reviewed against current PCGamingWiki coverage. SAVEDATA1000 naming is corroborated by long-running Steam/Nexus backup references.