Legendary Edition is a trilogy container, so the safest backup unit is the shared Save folder rather than one apparent slot. Keep the ME1/ME2/ME3 directory names intact because character-import workflows depend on the game-specific records remaining separated.
For this PC reference, the documented storage is Windows: %USERPROFILE%DocumentsBioWareMass Effect Legendary EditionSave. The known file or folder pattern is ME1, ME2, and ME3 subfolders under the Legendary Edition Save directory. The trilogy keeps each remastered game in its own subfolder beneath one Legendary Edition save root. Back up the whole Save directory when preserving a trilogy playthrough, especially before importing a character between games.
Backup guidance: Close Mass Effect Legendary Edition, let the launcher finish any synchronization, then copy the complete documented save directory to a dated folder outside the live path. Preserve companion files rather than selecting only the newest-looking record. EA/Steam cloud synchronization may coexist with the Documents copy; wait for sync to settle before replacing local files. Launcher and cloud context matters because The active EA app, Steam installation determines which local profile and cloud copy can overwrite the save. Identify the storefront and account before restoring files.
Compatibility and recovery should stay conservative. Treat saves as version-, storefront-, account-, and mod-sensitive unless the game or a separately verified migration workflow proves otherwise. A similar filename or extension is not evidence that two releases are interchangeable. If the expected progress is not visible, If progress is missing after a restore, confirm the active Windows account, storefront/profile, cloud state, and exact directory first. Restore the untouched backup before experimenting with individual files or older autosaves. 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.