diff --git a/src/datasets.jl b/src/datasets.jl
index ce50cfa2..15eb3643 100644
--- a/src/datasets.jl
+++ b/src/datasets.jl
@@ -367,7 +367,7 @@ end
     seek(io, header_offset)
     f.end_of_data = header_offset + fullsz
 
-    track!(wsession, data, header_offset)
+    track!(wsession, data, h5offset(f, header_offset))
 
     cio = begin_checksum_write(io, fullsz - 4)
     jlwrite(cio, ObjectStart(size_flag(psz)))