diff --git a/libs/ardour/ardour/file_source.h b/libs/ardour/ardour/file_source.h
index a63b447f92..ee01dfb356 100644
--- a/libs/ardour/ardour/file_source.h
+++ b/libs/ardour/ardour/file_source.h
@@ -56,6 +56,7 @@ public:
         void mark_immutable ();
         void mark_immutable_except_write();
 	void mark_nonremovable ();
+	void mark_removable ();
 
 	bool                 within_session () const { return _within_session; }
 	uint16_t             channel()         const { return _channel; }
diff --git a/libs/ardour/file_source.cc b/libs/ardour/file_source.cc
index 9cac4f0f4d..c9675df6ce 100644
--- a/libs/ardour/file_source.cc
+++ b/libs/ardour/file_source.cc
@@ -527,6 +527,12 @@ FileSource::mark_nonremovable ()
         _flags = Flag (_flags & ~(Removable|RemovableIfEmpty|RemoveAtDestroy));
 }
 
+void
+FileSource::mark_removable ()
+{
+        _flags = Flag (_flags | (Removable|RemovableIfEmpty|RemoveAtDestroy));
+}
+
 void
 FileSource::set_within_session_from_path (const std::string& path)
 {