A good pop-up blocker will not affect the booking system at all. We have tested the site with several different popup-blocker software products without any problems arising. We use popup windows and display layers for some purposes; help texts, longer lists and for the card payment window. Since you always request these by a click, they should display normally. If you still have a problem because you cannot see everything correctly, you can adjust the settings of the popup-blocker to temporarily disable the blocking or by adding the Stena Line web address to your list of safe sites. Problems can also occur because of Internet security software, see answer below.