Sega is aware that "a small number of users" appear to have had their Aliens: Colonial Marines save data wiped and progress reset.
The publisher: said: "We've received reports that a small number of users may be experiencing problems with saving their progress after completing the game's optional HDD install.
"If you experience any issues with your save game data, please try uninstalling the game from your HDD and playing from disc while we investigate what may be causing this issue."
The problem appears to be confined to the Xbox 360 version of the game, according to Polygon, which received the following comment from a representative at developer Gearbox: "If the support [forums] don't have this one indexed yet then it's still likely with QA getting a repro [reproduction of the issue] as the game just came out."
Aliens: Colonial Marines debuted at No.1 on the UK all formats chart this morning.
In our Aliens: Colonial Marines review we described the game as "a shooting gallery that fundamentally fails to understand what makes the Alien films so great."