You forgot to disable Steam Cloud. Even if you delete the cloud file, Steam re-downloads it. Disable Cloud, then put the console in Offline Mode once, edit, then go back online.
Summary
Copy the savegame.sav file to your desktop. Name it savegame_backup.sav . This is your safety net. If the editor bricks your file, you can restore this. resident evil revelations 2 save editor pc work