Skyrim Special Edition backups should include mod context, not just bytes. The base .ess file is the core save, but SKSE installations can add a matching .skse cosave and the save can reference plugins that are no longer installed. That means a technically intact file may still fail or behave differently on another setup. SaveEditor.com therefore treats the save file, its optional cosave, and the mod/load-order context as separate pieces of compatibility evidence.
For this PC reference, the documented storage is Windows: Steam: %USERPROFILE%DocumentsMy GamesSkyrim Special EditionSaves
GOG: %USERPROFILE%DocumentsMy GamesSkyrim Special Edition GOGSaves | Linux / Steam Play: Steam Play: <SteamLibrary-folder>/steamapps/compatdata/489830/pfx/. The known file or folder pattern is *.ess
*.skse (when created by SKSE). Base saves use .ess. Modded installations using SKSE can create a paired .skse cosave with the same base name. Treat paired files as one restore set when the mod stack depends on them.
Backup guidance: For an unmodded setup, back up the complete Saves folder. For SKSE/modded play, preserve matching .ess and .skse files plus a record of the mod list/load order. Steam Cloud, GOG Galaxy, Epic/Xbox cloud support, and optional OneDrive Documents backup can all affect which copy is restored. Launcher and cloud context matters because Steam and GOG use differently named Documents folders. Microsoft Store packaging differs and should not be treated as the same path simply because the game title is identical.
Compatibility and recovery should stay conservative. Original Skyrim saves can sometimes be used by Special Edition, but modded saves may fail when required plugins are missing or incompatible. If the expected progress is not visible, When a save fails after moving PCs, check the mod/plugin environment before assuming the .ess itself is corrupt. OneDrive can also redirect or synchronize the Documents folder unexpectedly. SaveEditor.com only labels a game-specific editor as available when a separate linked Tool has a verified operational runtime; this reference page by itself is not an editor claim.