diff --git a/windows/runner/win32_window.cpp b/windows/runner/win32_window.cpp
index 95ae3d0d..0c74b16a 100644
--- a/windows/runner/win32_window.cpp
+++ b/windows/runner/win32_window.cpp
@@ -110,7 +110,7 @@ bool Win32Window::CreateAndShow(const std::wstring& title,
   // Attempt to create a mutex to enforce single instance.
   CreateMutex(NULL, TRUE, L"com.yubico.authenticator.mutex");
   if (GetLastError() == ERROR_ALREADY_EXISTS) {
-      HWND handle=FindWindowA(NULL, "Yubico Authenticator");
+      HWND handle=FindWindow(L"FLUTTER_RUNNER_WIN32_WINDOW", L"Yubico Authenticator");
       WINDOWPLACEMENT place = { sizeof(WINDOWPLACEMENT) };
       GetWindowPlacement(handle, &place);
       switch(place.showCmd) {