diff --git a/es-app/src/FileFilterIndex.cpp b/es-app/src/FileFilterIndex.cpp
index 4f93cc079..8d4b53688 100644
--- a/es-app/src/FileFilterIndex.cpp
+++ b/es-app/src/FileFilterIndex.cpp
@@ -618,7 +618,7 @@ void FileFilterIndex::manageIndexEntry(std::map<std::string, int>* index,
     }
 }
 
-void FileFilterIndex::clearIndex(std::map<std::string, int> indexMap)
+void FileFilterIndex::clearIndex(std::map<std::string, int>& indexMap)
 {
     indexMap.clear();
 }
diff --git a/es-app/src/FileFilterIndex.h b/es-app/src/FileFilterIndex.h
index 6045a27c7..f7c081edb 100644
--- a/es-app/src/FileFilterIndex.h
+++ b/es-app/src/FileFilterIndex.h
@@ -81,7 +81,7 @@ private:
 
     void manageIndexEntry(std::map<std::string, int>* index, std::string key, bool remove);
 
-    void clearIndex(std::map<std::string, int> indexMap);
+    void clearIndex(std::map<std::string, int>& indexMap);
 
     std::string mTextFilter;
     bool mFilterByText;