diff --git a/btrbk b/btrbk
index 75a7b95..7dcd2ad 100755
--- a/btrbk
+++ b/btrbk
@@ -2085,6 +2085,7 @@ sub system_write_raw_info($$;@)
 
   # sort by %raw_info_sort, then by key
   my @line = $append ? () : ("#btrbk-v$VERSION", "# Do not edit this file");
+  push @line, '#t=' . time;
   foreach(sort { (($raw_info_sort{$a} // 99) <=> ($raw_info_sort{$b} // 99)) || ($a cmp $b) } keys %$raw_info) {
     push @line, ($_ . '=' . $raw_info->{$_});
   }