Back up the account folder with both SinglePlayer and Multiplayer branches as needed. For co-op, identify the host because the host save carries the persistent world state.
For this PC reference, the documented storage is Windows: %USERPROFILE%AppDataLocalLowSKSTheForest<account-id>. The known file or folder pattern is SinglePlayer and Multiplayer save-slot directories. The Forest stores local progression under LocalLow in account-specific single-player/multiplayer trees. A slot is a directory of related files, not one standalone save.
Backup guidance: Close The Forest, 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. Steam Cloud can synchronize the LocalLow data; multiplayer host saves remain different from a joining client's state. Launcher and cloud context matters because The active 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.