Even though the user has the permission to access the site and they can view other content on the SPS 2013 homepage. Not sure why few users cant see the TOP navigation bar.
I have logging with my credentials from there machine and it works fine. Its only happening when the user logs with their credentials. So far it seems a credentials issue, but wondering what more to enabled apart from allowing them to access the intranet and that is what they have it as can access the homepage and view other content on the homepage.