A thread on the official Microsoft Xbox forum suggests console users are experiencing serious issues with their achievements and Gamerscores.
The twelve pages of complaints all report similar issues, a severe drop in Gamerscore points accompanied by a loss of previous achievements.
The official Xbox support Twitter account has reported that it's looking in to the issue, and asked those experiencing it to try re-downloading their profiles.
Some users have reported receiving a message about their profile being used on a different console before the points and achievements disappeared.
One of the user posts even suggests a routine update might be at fault.
"I called up Xbox support and they said they are in the process of an update rollout which is what is causing this, they said they hope to have everybody back to normal by tomorrow, if not you should call back again."
Eurogamer has also heard from displeased consumers.
Microsoft has been contacted for comment.