A number of Watch Dogs players claim the title's uPlay rewards system has prevented them from loading their game saves.
In a large thread on Ubisoft's official Watch Dogs forum, hundreds of gamers are reporting the apparent bug.
They say problems arise when they redeem special content through the game's uPlay rewards screen.
Players signed into uPlay can earn reward points while playing, which can then be spent on exclusive content such as a gold-coloured D50 gun and a Papavero Stealth Edition car.
However, some players are reporting that after redeeming these rewards, the game refuses to load their save, instead freezing at the 90 per cent mark.
The forum thread was started on May 27, the day the game was released. More than a week later, some users have yet to have the problem resolved.
"WTF UBISOFT?!?! its been over a week and the game still doesn't work," one user commented.
"I had fun [with the game]," stated another, "but after losing so many hours worth of game time, I don't even want to play the game anymore."
Ubisoft posted a tweet on Tuesday stating that it was aware of the problem: "We're aware some of you are stuck on the loading screen. We're hard at work on isolating the problem to find a fix.
"If you're encountering that issue, please submit a ticket to http://support.ubi.com to help move forward. Thanks for understanding."