The HD Remaster is one PC product but it contains several distinct save contexts, so backing up only the first save-looking file is risky. Steam places the collection under one Documents root; Microsoft Store uses WGS. SaveEditor recommends preserving the collection root and labeling the backup with which component game and slot were active. That matters when troubleshooting because Final Fantasy X, X-2, and Last Mission can each have their own progress while sharing the same installation and launcher.
Known Final Fantasy X/X-2 HD Remaster save-file structure
The researched filename or folder pattern is Separate game-specific save data exists beneath the remaster root for Final Fantasy X, X-2, and Last Mission.. File-extension context: No single extension is sufficient to identify every relevant save record. The documented format notes are: The collection contains multiple games under one product. Steam uses the Documents tree while Microsoft Store uses a WGS container. Steam Cloud quotas are tracked separately for FFX, X-2, and Last Mission.
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 backup for one title in the collection should not overwrite another title’s data. Steam and Microsoft Store use different storage containers even when the underlying game progress is related. 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%DocumentsSQUARE ENIXFINAL FANTASY X&X-2 HD Remaster ; Microsoft Store: %LOCALAPPDATA%Packages39EA002F.FFXX-2HDRemaster_n746a19ndrrjgSystemAppDatawgs 009000000B904E5_0000000000000000000000006038DDC9<container>. Storefront context: Steam, Microsoft Store. Do not assume a save from FFX belongs in the same subfolder as X-2 or Last Mission. Microsoft Store container names are not user-friendly filenames. 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 the whole FINAL FANTASY X&X-2 HD Remaster directory on Steam so all game-specific subfolders and system data remain together. For WGS, preserve the complete container tree. 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 are documented; OneDrive can also synchronize the Documents root when enabled. 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 save appears absent, confirm whether you launched X, X-2, or Last Mission and whether OneDrive/Steam Cloud restored a different Documents copy. Microsoft Store users should verify the correct WGS account container. Those questions require a verified parser/profile or a game-specific source, not a generic format guess.
Verification context: Reviewed against current PCGamingWiki Final Fantasy X/X-2 HD Remaster save-location and cloud documentation.