diff --git a/src/calibre/utils/windows/common.h b/src/calibre/utils/windows/common.h
index 1ad3190ef3..2d60c8b366 100644
--- a/src/calibre/utils/windows/common.h
+++ b/src/calibre/utils/windows/common.h
@@ -58,8 +58,8 @@ class scoped_com_initializer {  // {{{
 
 #define INITIALIZE_COM_IN_FUNCTION scoped_com_initializer com; if (!com) return com.set_python_error();
 
-static inline void com_wchar_raii_free(wchar_t *x) { CoTaskMemFree(x); }
-typedef generic_raii<wchar_t*, com_wchar_raii_free> com_wchar_raii;
+static inline void co_task_mem_free(wchar_t *x) { CoTaskMemFree(x); }
+typedef generic_raii<wchar_t*, co_task_mem_free> com_wchar_raii;
 
 static inline void mapping_raii_free(void *x) { UnmapViewOfFile(x); }
 typedef generic_raii<void*, mapping_raii_free> mapping_raii;