Persona 3 Reload has unusually useful public Steam Cloud metadata: SteamDB shows the exact WinAppDataRoaming root and SaveData*.sav pattern. That makes the Steam backup boundary clear, but it does not solve Microsoft Store compatibility because the Game Pass version lives in WGS and community transfer workflows use conversion/encryption-aware tools. SaveEditor therefore documents both locations while explicitly separating “where the file is” from “whether it is directly compatible.” A safe migration starts with a complete backup of both source and target directories.
Prepare the source PC
On the source system, identify the actual Persona 3 Reload save root: Windows: Steam: %APPDATA%SEGAP3RSteam<64-bit-SteamID> ; Microsoft Store: %LOCALAPPDATA%PackagesSEGAofAmericaInc.L0cb6b3aea_s751p9cej88mtSystemAppDatawgs<user-id>. The expected file/folder pattern is Steam: SaveData*.sav; Microsoft Store: opaque WGS files/containers.. Close the game, let the active launcher finish writing and synchronizing, then make a complete offline copy rather than transferring a file that may still be open.
Preserve storefront and profile identity
Documented storefronts: Steam, Microsoft Store. The Steam and Microsoft Store save containers are not equivalent. Do not rename an arbitrary WGS file to SaveData001.sav and assume it is valid. A transfer between two PCs is simplest when both systems use the same storefront/account/profile context. If the destination uses a different store or container, treat that as a migration problem rather than an ordinary restore.
Move the complete save boundary
Copy the complete Steam-ID directory or the complete Microsoft WGS tree before any transfer. Keep original SaveData files untouched until the migrated save has been loaded and re-saved successfully. Put the copied data on the destination only after confirming the destination save path. If the game creates a new empty save first, keep that new folder as another backup so you can compare structures and revert.
Handle cloud sync deliberately
Steam Cloud and Xbox Cloud are documented. SteamDB reports a 550 MiB cloud quota and the SaveData*.sav pattern for Steam. Decide whether the local transferred copy or cloud copy should be authoritative before launching the game. If possible, preserve both. After the transferred save loads correctly, make a fresh in-game save and let the launcher synchronize normally.
Check compatibility before blaming the transfer
Steam cloud configuration explicitly maps WinAppDataRoaming/SEGA/P3R/Steam/{64BitSteamID} with a SaveData*.sav pattern. Microsoft Store uses WGS and transfer to Steam may require format/encryption-aware tooling. Compatibility note: Game Pass-to-Steam migration can require encryption/container conversion. The existence of both files on disk does not make them byte-compatible. If the destination does not see the transferred progress, If Steam does not show an imported slot, confirm the 64-bit Steam ID folder and SaveData numbering. For Microsoft Store migration, restore the original WGS copy if a conversion tool fails. Verify game edition/version, store, profile IDs, redirected folders, and mod/DLC dependencies before editing the save itself.
Verification context: Reviewed against PCGamingWiki Persona 3 Reload and current SteamDB user-file-system mapping for app 2161700.