diff --git a/cura/Machines/Models/MaterialManagementModel.py b/cura/Machines/Models/MaterialManagementModel.py
index ea7a26796e..ae86e609ee 100644
--- a/cura/Machines/Models/MaterialManagementModel.py
+++ b/cura/Machines/Models/MaterialManagementModel.py
@@ -41,7 +41,7 @@ class MaterialManagementModel(QObject):
         a message prompting the user to sync the materials with their printers.
         """
         application = cura.CuraApplication.CuraApplication.getInstance()
-        for package_id, package_data in application.getPackageManager().installed_packages.items():
+        for package_id, package_data in application.getPackageManager().getPackagesInstalledOnStartup().items():
             if package_data["package_info"]["package_type"] == "material":
                 # At least one new material was installed
                 self._showSyncNewMaterialsMessage()