Cult of the Lamb keeps multiple slot/backup records. Copy the entire saves directory before trying an older generation, and work on duplicates rather than the only live file.
For this PC reference, the documented storage is Windows: %USERPROFILE%AppDataLocalLowMassive MonsterCult Of The Lambsaves. The known file or folder pattern is slot records and automatic backup generations in the saves directory. Cult of the Lamb stores slot-oriented saves beneath LocalLow. Related backup generations can be valuable for recovery, so preserve the entire saves directory before replacements.
Backup guidance: Close Cult of the Lamb, 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. Cloud synchronization can overwrite a manual restore; complete sync and keep an offline copy first. Launcher and cloud context matters because The active Steam, GOG 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.