Guild Wars 2

There are 2 seperate windows that pop open, the first is the repair achive tool and it gets to 50% and then stops, then the downloader starts again and starts from the beginning

Ok, i have tried to download this game 4 times now and the same thing keeps happening. Something always happens and I have to shut my computer off or power goes out, etc. I can see that there is over 12GB of data stored in the folder but when i open the downloader again it tries to start the entire download over. The repair process gets to 50% and then the downloader opens and tries to download all 218,000+ files again. Any ideas on what is causing the downloader to not recognise that it has already downloaded over 60% of the files?