diff --git a/src/OpenFOAM/containers/HashTables/HashTable/HashTableI.H b/src/OpenFOAM/containers/HashTables/HashTable/HashTableI.H
index b3e3406da..83c8a394c 100644
--- a/src/OpenFOAM/containers/HashTables/HashTable/HashTableI.H
+++ b/src/OpenFOAM/containers/HashTables/HashTable/HashTableI.H
@@ -115,6 +115,7 @@ inline T& Foam::HashTable<T, Key, Hash>::operator[](const Key& key)
     if (iter == this->end())
     {
         FatalErrorInFunction
+            << key << " not found in table.  Valid entries: "
             << toc()
             << exit(FatalError);
     }
@@ -131,6 +132,7 @@ inline const T& Foam::HashTable<T, Key, Hash>::operator[](const Key& key) const
     if (iter == this->cend())
     {
         FatalErrorInFunction
+            << key << " not found in table.  Valid entries: "
             << toc()
             << exit(FatalError);
     }