diff --git a/src/app_controller.py b/src/app_controller.py
index cc5ba00f..dae12c96 100644
--- a/src/app_controller.py
+++ b/src/app_controller.py
@@ -2213,10 +2213,20 @@ class AppController:
   if not self.active_project_path:
    name = self.project.get("project", {}).get("name", "project")
    fallback_path = f"{name}.toml"
-   project_manager.save_project(self.project, fallback_path)
-   self.active_project_path = fallback_path
-   if fallback_path not in self.project_paths:
-    self.project_paths.append(fallback_path)
+   try:
+    project_manager.save_project(self.project, fallback_path)
+    self.active_project_path = fallback_path
+    if fallback_path not in self.project_paths:
+     self.project_paths.append(fallback_path)
+   except (OSError, IOError, PermissionError) as e:
+    logging.getLogger(__name__).debug(
+     "Could not save fallback project to %s: %s", fallback_path, e,
+     extra={"source": "app_controller._load_active_project.fallback_save"},
+    )
+    # The save is best-effort; the app can still operate without persisting
+    # the empty fallback (e.g., when the test sandbox FR1 guard blocks
+    # writes to the project root). active_project_path stays empty;
+    # the next save will use a proper path.
   self.preset_manager = presets.PresetManager(Path(self.active_project_path).parent if self.active_project_path else None)
   self.tool_preset_manager = tool_presets.ToolPresetManager(Path(self.active_project_path).parent if self.active_project_path else None)
   from src.personas import PersonaManager