diff --git a/src/calibre/gui2/__init__.py b/src/calibre/gui2/__init__.py
index ba8a369d1f..564edeaddd 100644
--- a/src/calibre/gui2/__init__.py
+++ b/src/calibre/gui2/__init__.py
@@ -1471,12 +1471,13 @@ empty_index = empty_model.index(0)
 def set_app_uid(val):
     import ctypes
     from ctypes import wintypes
+    from ctypes import HRESULT
     try:
         AppUserModelID = ctypes.windll.shell32.SetCurrentProcessExplicitAppUserModelID
     except Exception:  # Vista has no app uids
         return False
     AppUserModelID.argtypes = [wintypes.LPCWSTR]
-    AppUserModelID.restype = wintypes.HRESULT
+    AppUserModelID.restype = HRESULT
     try:
         AppUserModelID(unicode_type(val))
     except Exception as err: