diff --git a/src/library.cpp b/src/library.cpp
index 79ccbf044..760e3d142 100644
--- a/src/library.cpp
+++ b/src/library.cpp
@@ -274,11 +274,8 @@ bool Library::writeToFile(const std::string& path) const
 bool Library::writeBookmarksToFile(const std::string& path) const
 {
   LibXMLDumper dumper(this);
-  std::string xml;
-  {
-    std::lock_guard<std::mutex> lock(m_mutex);
-    xml = dumper.dumpLibXMLBookmark();
-  };
+  // NOTE: LibXMLDumper::dumpLibXMLBookmark uses Library in a thread-safe way
+  const std::string xml = dumper.dumpLibXMLBookmark();
   return writeTextFile(path, xml);
 }
 
diff --git a/src/libxml_dumper.cpp b/src/libxml_dumper.cpp
index 5a681e861..db03a2005 100644
--- a/src/libxml_dumper.cpp
+++ b/src/libxml_dumper.cpp
@@ -91,7 +91,7 @@ void LibXMLDumper::handleBookmark(Bookmark bookmark, pugi::xml_node root_node) {
   auto book_node = entry_node.append_child("book");
 
   try {
-    auto book = library->getBookById(bookmark.getBookId());
+    auto book = library->getBookByIdThreadSafe(bookmark.getBookId());
     ADD_TEXT_ENTRY(book_node, "id", book.getId());
     ADD_TEXT_ENTRY(book_node, "title", book.getTitle());
     ADD_TEXT_ENTRY(book_node, "language", book.getLanguage());