diff --git a/internal/handlers/dashboard.go b/internal/handlers/dashboard.go
index 895e321..5c199e5 100644
--- a/internal/handlers/dashboard.go
+++ b/internal/handlers/dashboard.go
@@ -210,9 +210,20 @@ func (h *DashboardHandler) GetPreferences(c echo.Context) error {
 	if err != nil {
 		return c.JSON(http.StatusNotFound, map[string]string{"error": "Preferences not found"})
 	}
+
+	// Normalize nil slices to empty arrays for JSON
+	hiddenCollections := prefs.HiddenCollections
+	if hiddenCollections == nil {
+		hiddenCollections = []string{}
+	}
+	collectionOrder := prefs.CollectionOrder
+	if collectionOrder == nil {
+		collectionOrder = []string{}
+	}
+
 	return c.JSON(http.StatusOK, map[string]interface{}{
-		"hidden_collections": prefs.HiddenCollections,
-		"collection_order":   prefs.CollectionOrder,
+		"hidden_collections": hiddenCollections,
+		"collection_order":   collectionOrder,
 		"items_per_section":  prefs.ItemsPerSection.Int32,
 	})
 }