diff --git a/script/download-file/customize.py b/script/download-file/customize.py
index 97969418c6..9918de7c3f 100644
--- a/script/download-file/customize.py
+++ b/script/download-file/customize.py
@@ -206,7 +206,7 @@ def preprocess(i):
     if not pre_clean:
         env['CM_PRE_DOWNLOAD_CMD'] = ''
 
-    if os_info['platform'] == 'windows':
+    if os_info['platform'] == 'windows' and env.get('CM_DOWNLOAD_CMD', '') != '':
         env['CM_DOWNLOAD_CMD'] =  env['CM_DOWNLOAD_CMD'].replace('&', '^&').replace('|', '^|').replace('(', '^(').replace(')', '^)')
         if pre_clean:
             env['CM_PRE_DOWNLOAD_CLEAN_CMD'] = "del /Q %CM_DOWNLOAD_FILENAME%"