diff --git a/tests/core_tests/chaingen_main.cpp b/tests/core_tests/chaingen_main.cpp
index c2be845e..30cbeaa4 100644
--- a/tests/core_tests/chaingen_main.cpp
+++ b/tests/core_tests/chaingen_main.cpp
@@ -63,7 +63,7 @@ bool clean_data_directory()
 
   for(auto& entry : boost::make_iterator_range(boost::filesystem::directory_iterator(config_folder), {}))
   {
-    const std::string& fn_str = entry.path().filename().string();
+    std::string fn_str = entry.path().filename().string();
     if (files.count(fn_str) != 0)
     {
       entries_to_remove.push_back(entry.path());