diff --git a/packages/editor/src/components/editor/index.tsx b/packages/editor/src/components/editor/index.tsx
index 88e96497..6433940a 100644
--- a/packages/editor/src/components/editor/index.tsx
+++ b/packages/editor/src/components/editor/index.tsx
@@ -72,6 +72,7 @@ const PAINT_CURSOR_BADGE_COLOR = '#818cf8'
 const PAINT_CURSOR_BADGE_DISABLED_COLOR = '#94a3b8'
 const PAINT_CURSOR_BADGE_OFFSET_X = 14
 const PAINT_CURSOR_BADGE_OFFSET_Y = 14
+const SCENE_READY_FALLBACK_MS = 8000
 const EDITOR_HOVER_STYLES: HoverStyles = {
   default: { visibleColor: 0x00_aa_ff, hiddenColor: 0xf3_ff_47, strength: 5, pulse: true },
   delete: { visibleColor: 0xef_44_44, hiddenColor: 0x99_1b_1b, strength: 6, pulse: false },
@@ -1059,6 +1060,19 @@ export default function Editor({
     setIsViewerSceneReady(ready)
   }, [])
 
+  useEffect(() => {
+    if (isLoading || isSceneLoading || !hasLoadedInitialScene || isViewerSceneReady) return
+
+    const timer = window.setTimeout(() => {
+      console.warn('[editor] viewer scene readiness timed out; showing editor shell anyway', {
+        sceneReadyKey,
+      })
+      setIsViewerSceneReady(true)
+    }, SCENE_READY_FALLBACK_MS)
+
+    return () => window.clearTimeout(timer)
+  }, [hasLoadedInitialScene, isLoading, isSceneLoading, isViewerSceneReady, sceneReadyKey])
+
   const showLoader = isLoading || isSceneLoading || !hasLoadedInitialScene || !isViewerSceneReady
 
   const firstPersonPreviousLevelRef = useRef(useViewer.getState().selection.levelId)
diff --git a/packages/viewer/src/lib/materials.ts b/packages/viewer/src/lib/materials.ts
index 9feadd5f..090971fa 100644
--- a/packages/viewer/src/lib/materials.ts
+++ b/packages/viewer/src/lib/materials.ts
@@ -71,7 +71,7 @@ export function resolveSurfaceColor(
   // The active scene theme may tint individual roles (e.g. Mediterranean's blue
   // roof); fall back to the chosen colour preset's palette when it doesn't.
   const tints = sceneThemeId ? getSceneTheme(sceneThemeId).clayTints : undefined
-  return tints?.[role] ?? PRESET_PALETTES[preset][role]
+  return tints?.[role] ?? (PRESET_PALETTES[preset] ?? CLAY_PALETTE)[role]
 }
 
 // DoubleSide on any NodeMaterial inside the MRT scenePass (SSGI's output /
diff --git a/packages/viewer/src/store/use-viewer.ts b/packages/viewer/src/store/use-viewer.ts
index c1da8e44..11cc67e3 100644
--- a/packages/viewer/src/store/use-viewer.ts
+++ b/packages/viewer/src/store/use-viewer.ts
@@ -7,6 +7,7 @@ import { create } from 'zustand'
 import { persist } from 'zustand/middleware'
 import type { EdgeMode } from '../lib/edge-style'
 import type { ColorPreset, RenderShading } from '../lib/materials'
+import { SCENE_THEME_IDS } from '../lib/scene-themes'
 
 export type RenderContext = 'editor' | 'viewer'
 
@@ -114,6 +115,85 @@ type ViewerState = {
   setInputDragging: (dragging: boolean) => void
 }
 
+type PersistedViewerState = Partial<
+  Pick<
+    ViewerState,
+    | 'cameraMode'
+    | 'sceneTheme'
+    | 'shadingByContext'
+    | 'textures'
+    | 'colorPreset'
+    | 'edges'
+    | 'shadows'
+    | 'unit'
+    | 'levelMode'
+    | 'wallMode'
+    | 'projectPreferences'
+  >
+>
+
+const CAMERA_MODES = ['perspective', 'orthographic'] as const
+const RENDER_SHADINGS = ['solid', 'rendered'] as const
+const COLOR_PRESETS = ['clay', 'white', 'mono', 'blueprint'] as const
+const EDGE_MODES = ['off', 'soft', 'strong'] as const
+const UNITS = ['metric', 'imperial'] as const
+const LEVEL_MODES = ['stacked', 'exploded', 'solo', 'manual'] as const
+const WALL_MODES = ['up', 'cutaway', 'down'] as const
+
+function pickString<T extends string>(value: unknown, allowed: readonly T[], fallback: T): T {
+  return typeof value === 'string' && allowed.includes(value as T) ? (value as T) : fallback
+}
+
+function normalizeShadingByContext(value: unknown): ViewerState['shadingByContext'] {
+  if (!value || typeof value !== 'object' || Array.isArray(value)) return {}
+
+  const next: ViewerState['shadingByContext'] = {}
+  for (const [context, shading] of Object.entries(value)) {
+    if (context !== 'editor' && context !== 'viewer') continue
+    next[context] = pickString<RenderShading>(shading, RENDER_SHADINGS, 'rendered')
+  }
+  return next
+}
+
+function normalizeProjectPreferences(value: unknown): ViewerState['projectPreferences'] {
+  if (!value || typeof value !== 'object' || Array.isArray(value)) return {}
+
+  const next: ViewerState['projectPreferences'] = {}
+  for (const [projectId, preferences] of Object.entries(value)) {
+    if (!preferences || typeof preferences !== 'object' || Array.isArray(preferences)) continue
+    const record = preferences as Record<string, unknown>
+    next[projectId] = {
+      ...(typeof record.showScans === 'boolean' ? { showScans: record.showScans } : {}),
+      ...(typeof record.showGuides === 'boolean' ? { showGuides: record.showGuides } : {}),
+      ...(typeof record.showGrid === 'boolean' ? { showGrid: record.showGrid } : {}),
+    }
+  }
+  return next
+}
+
+function normalizePersistedViewerState(value: unknown): PersistedViewerState {
+  if (!value || typeof value !== 'object' || Array.isArray(value)) return {}
+  const state = value as Record<string, unknown>
+
+  return {
+    cameraMode: pickString<ViewerState['cameraMode']>(
+      state.cameraMode,
+      CAMERA_MODES,
+      'perspective',
+    ),
+    sceneTheme: pickString(state.sceneTheme, SCENE_THEME_IDS, 'studio'),
+    shadingByContext: normalizeShadingByContext(state.shadingByContext),
+    textures: typeof state.textures === 'boolean' ? state.textures : true,
+    colorPreset: pickString<ColorPreset>(state.colorPreset, COLOR_PRESETS, 'clay'),
+    edges: pickString<EdgeMode>(state.edges, EDGE_MODES, 'soft'),
+    shadows: typeof state.shadows === 'boolean' ? state.shadows : true,
+    unit: pickString<ViewerState['unit']>(state.unit, UNITS, 'metric'),
+    levelMode: pickString<ViewerState['levelMode']>(state.levelMode, LEVEL_MODES, 'stacked'),
+    wallMode: pickString<ViewerState['wallMode']>(state.wallMode, WALL_MODES, 'up'),
+    projectPreferences: normalizeProjectPreferences(state.projectPreferences),
+  }
+}
+
 const useViewer = create<ViewerState>()(
   persist(
     (set) => ({
@@ -267,6 +347,10 @@ const useViewer = create<ViewerState>()(
     }),
     {
       name: 'viewer-preferences',
+      merge: (persistedState, currentState) => ({
+        ...currentState,
+        ...normalizePersistedViewerState(persistedState),
+      }),
       partialize: (state) => ({
         cameraMode: state.cameraMode,
         sceneTheme: state.sceneTheme,