Ubisoft warns that some players "may experience long delays when trying to login" to its servers in order to play the PC version of Watch Dogs, rendering the game unplayable on launch day.
An influx of new players apparently overwhelmed Ubisoft's authentication services, leaving some unable to join or log in to Ubisoft's uPlay network. Kotaku reports that players are experiencing a number of issues as a result, including stalled downloads, in-game crashes, and unrecoverable errors.
Ubisoft has not issued a timeframe for a fix, but notes that affected customers should "stay tuned" for updates.