diff --git a/src/@dseries/save.m b/src/@dseries/save.m
index 00a5a7b84ce0ea0934d0d56b6a2e970613ac5156..52c678b4288a5149fd9a142407e03ecd0fbc8c2e 100644
--- a/src/@dseries/save.m
+++ b/src/@dseries/save.m
@@ -72,7 +72,7 @@ switch format
     if ~isempty(fieldnames(o.tags))
         % User has defined tags on the variables.
         tagnames = fieldnames(o.tags);
-        TAGS__ = fprintf(fid, 'struct();\n');
+        fprintf(fid, 'TAGS__ = struct();\n');
         for i=1:length(tagnames)
             fprintf(fid, 'TAGS__.%s = cell(%s, 1);\n', tagnames{i}, num2str(vobs(o)));
             for j=1:vobs(o)