diff --git a/xrootd/XrdxCastor2Ofs.cpp b/xrootd/XrdxCastor2Ofs.cpp
index 5ff3f34f381918d6512dbf9ce4f772ce402b543c..6fab7713b67caf1ad5e9a8d3ec6d18a00da71963 100644
--- a/xrootd/XrdxCastor2Ofs.cpp
+++ b/xrootd/XrdxCastor2Ofs.cpp
@@ -730,7 +730,7 @@ XrdxCastor2OfsFile::BuildTransferId(const char* tident, XrdOucEnv* env)
       << "\"" << castor_path << "\", "
       << "\"" << tx_type << "\", "
       << "\"" << mIsRW << "\", "
-      << "\"" << mReqId
+      << "\"" << mReqId << "\""
       << ")";
 
   mTransferId = oss.str();