diff --git a/Common/Options.cpp b/Common/Options.cpp
index 33f4f651c88ae17d62d95d265ad1d9a831065963..657064bec7522867529c92e5533fc26208b02d20 100644
--- a/Common/Options.cpp
+++ b/Common/Options.cpp
@@ -5716,7 +5716,7 @@ double opt_view_nb_non_empty_timestep(OPT_ARGS_NUM)
   GET_VIEW(0.);
   if(!data) return 0;
   int n = 0;
-  for(unsigned int i = 0; i < data->getNumTimeSteps(); i++)
+  for(int i = 0; i < data->getNumTimeSteps(); i++)
     if(data->hasTimeStep(i)) n++;
   return n;
 #else