diff --git a/dlls/winex11.drv/settings.c b/dlls/winex11.drv/settings.c
index d530f9bc167..116bf1506ef 100644
--- a/dlls/winex11.drv/settings.c
+++ b/dlls/winex11.drv/settings.c
@@ -176,6 +176,7 @@ static BOOL read_registry_settings(DEVMODEW *dm)
         return FALSE;
 
 #define query_value(name, data) \
+    size = sizeof(DWORD); \
     if (RegQueryValueExA(hkey, name, 0, &type, (LPBYTE)(data), &size) || \
         type != REG_DWORD || size != sizeof(DWORD)) \
         ret = FALSE