diff --git a/libsrc/core/archive.hpp b/libsrc/core/archive.hpp
index dc381a4a..2a006693 100644
--- a/libsrc/core/archive.hpp
+++ b/libsrc/core/archive.hpp
@@ -918,7 +918,7 @@ namespace ngcore
   {
     size_t hash_value;
     char* h;
-    int offset;
+    int offset = 0;
   public:
     HashArchive() : Archive(true)
       { h = (char*)&hash_value; }