diff --git a/scripts/cleanup/unusued_compilation.py b/scripts/cleanup/unusued_compilation.py
index 6ad1e2da4d..4515a663af 100644
--- a/scripts/cleanup/unusued_compilation.py
+++ b/scripts/cleanup/unusued_compilation.py
@@ -77,7 +77,7 @@ def is_excluded(file):
     return False
 
 def filter_from_processed(filelist, filter_file_path):
-    filelist = [f for f in filelist if not is_excluded(f)]
+    filelist = set([f for f in filelist if not is_excluded(f)])
     if os.path.exists(filter_file_path):  
         with open(filter_file_path, 'r') as filter_file:
             processed_files = [s.strip() for s in filter_file.readlines()]