When you edit a script (the .rpy files) while a game is running, Ren’Py attempts to "hot-reload" those changes. However, if you change a variable name or delete a label that a save file is currently pointing to, the game will crash. This is where "patching" becomes essential. How to Patch a Ren’Py Game via the Editor
To resolve the "Ren'Py editor save patched" issue, try the following troubleshooting steps: renpy editor save patched
Background: Ren'Py save system overview