diff --git a/programs/explorer/desktop.c b/programs/explorer/desktop.c
index 94d178880a8..51d1535aea6 100644
--- a/programs/explorer/desktop.c
+++ b/programs/explorer/desktop.c
@@ -1219,6 +1219,7 @@ static HRESULT WINAPI shellwindows_Register(IShellWindows *iface,
     window->hwnd = hwnd;
     window->class = class;
     *cookie = window->cookie = ++cookie_counter;
+    window->pidl = NULL;
 
     LeaveCriticalSection(&sw->cs);
     return S_OK;