Guild Wars 2 sold a million units prior to the game's official launch yesterday, according to developer ArenaNet.
"This is the culmination of a 5-year journey and to be greeted by this level of enthusiasm by our fans is truly amazing," said ArenaNet president and co-founder Mike O'Brien.
"But really our work is just beginning. Now our focus is shifting to building on this living world we've delivered, continuously refining our game and improving services to ensure our players have the best possible experience."
Those who pre-ordered the game were rewarded with access last weekend, and over 400,000 players were simultaneously online, according to ArenaNet.
Unfortunately, a number of connections problems including a grouping bug quickly surfaced.
"We currently have a couple serious bugs with one of our important back end systems. This error is causing the loss of trading post, players to sometimes be separated and unable to travel to each other when switching maps and entering overflow servers, and numerous guild errors," said ArenaNet.
"We are very sorry for this inconvenience and are currently working around the clock to try and remedy this error."
"When this bug is fixed overflow servers will keep parties together and players will be able to travel to the same overflow server as any friend or guild member who is in an overflow."
A patch was being worked on, said the developer.