Ubisoft is working on a fix for an Assassin's Creed III bug that wipes users' save data.
The deletion occurs if a save game is loaded while the game’s Hidden Secrets DLC is being downloaded, said Ubisoft.
It appears to only affect PlayStation 3 and Xbox 360 versions of the game, but has affected a number of players already.
"We're able to reproduce this issue at the studio and are working on a fix/workaround," said Ubisoft Montreal community developer Gabe Graziani.
"From what we can tell, this problem seems to be rare and should generally only affect a very small number of players. That said, we're taking the speedy and complete resolution of this very seriously."
The Hidden Secrets DLC is currently only available to Season Pass holders.
Ubisoft has issued the following advice:
"AVOIDING THIS BUG: Do not load your saved AC3 game while the DLC is downloading in the background. This appears to be the key trigger for this bug. You can do anything else you want to do, just don't load up your saved game and play it while the DLC is downloading."