The latest Crackdown downloadable content included a bug that's been responsible for resetting saved game files.
No solution has yet been found, but developer Realtime Worlds has assured us that it's being worked on.
"We are aware that the recently released Crackdown DLC is causing some gamers to experience a reset of their saved games when they engage in co-op play," said the developer in the official forum. "The team is working extremely hard to identify the issue and has provided steps to avoid the problem."
The errors arose when players installed the new content and joined or hosted an online co-op game immediately afterwards. And if you're one of those who's already experienced this, then it's unlikely you'll get your saved files back.
However, Realtime Worlds has offered advice on what to do to avoid the problem. After downloading the update and one or more of the content packs, simply play a solo campaign and move somewhere in the world (into the Agency garage or onto the other side of a supply point).
Pause the game and then quit, and it will automatically save your progress. You'll then be free to hop online and play until your heart's content. But be sure that whoever you're playing with on Live has done the same thing, otherwise you'll still be at risk.
The updates were added late last week. Alongside a host of game tweaks were two new content packs: "Getting Busy" for 800 points and "Free-For-All" for nothing. They added new weapons, vehicles, game types, cheat modes, super-powers and more to the already heady-blend of action.
You can read a full list of Crackdown DLC additions elsewhere on Eurogamer.