diff --git a/src/mapped_storage.cpp b/src/mapped_storage.cpp
index e80b48661..d0368dbd4 100644
--- a/src/mapped_storage.cpp
+++ b/src/mapped_storage.cpp
@@ -125,7 +125,7 @@ namespace libtorrent
 				return *this;
 			}
 
-			bool valid() const { return m_entry; }
+			bool valid() const { return m_entry && m_entry->file.const_data(); }
 
 			char* addr() const
 			{