diff --git a/src/storage.cpp b/src/storage.cpp
index fee718732..888b26390 100755
--- a/src/storage.cpp
+++ b/src/storage.cpp
@@ -116,6 +116,7 @@ namespace
 
 		boost::shared_ptr<file> open_file(path const& p, file::open_mode m)
 		{
+			assert(p.is_complete());
 			typedef std::map<path, file_entry>::iterator iterator;
 			iterator i = m_files.find(p);
 			if (i != m_files.end())