Thank you for your explanation. In my survey restarting can hurt only the participant though, since a few first questions are always the same "warm up" ones, and the others are presented randomly, and they are quite numerous.
I cleared the cookie by using another workaround, by uploading this jQuery plugin in the template directory:
plugins.jquery.com/cookie/
Then including it in the startpage.pstpl
Code:
{TEMPLATEJS}
<script type="text/javascript" src="{TEMPLATEURL}jquery.cookie.js"></script>
And I cleared the cookie by inserting this code in a introductory "Text Display" question
Code:
<script type="text/javascript" charset="utf-8">
$(document).ready(function(){
if (typeof $.cookie('limesurvey_timers') === 'undefined'){
} else {
$.cookie('limesurvey_timers', null, { path: '/' });
}
});
</script>