diff --git a/vcl/source/uitest/uno/uitest_uno.cxx b/vcl/source/uitest/uno/uitest_uno.cxx
index 83355b3a5894..4840934e8d13 100644
--- a/vcl/source/uitest/uno/uitest_uno.cxx
+++ b/vcl/source/uitest/uno/uitest_uno.cxx
@@ -70,6 +70,7 @@ void SAL_CALL UITestUnoObj::executeCommand(const OUString& rCommand)
 css::uno::Reference<css::ui::test::XUIObject> SAL_CALL UITestUnoObj::getTopFocusWindow()
     throw (css::uno::RuntimeException, std::exception)
 {
+    SolarMutexGuard aGuard;
     std::unique_ptr<UIObject> pObj = UITest::getFocusTopWindow();
     return new UIObjectUnoObj(std::move(pObj));
 }