Rocksteady is investigating an issue that renders Batman: Arkham City, out in the UK today, unplayable.
Some gamers have reported being booted out of the game after receiving a "downloadable content is corrupt" error message, preventing further progress.
Rocksteady said it was aware of the issue and was working to fix it.
"We are receiving reports of this happening to a small percentage of people and are looking into it," European community manager Sarah Wellock wrote on the Batman: Arkham City forum.
"I am speaking to our team to see if there is a way to resolve it."
In the meantime, Wellock recommended players suffering from the problem delete the DLC and then reinstall.
In a later post, Wellock suggested the issue may be the result of problems with PlayStation Network and Xbox Live.
"The game is released now because it passed all the vigorous tests, the problems we are experiencing now are Microsoft/Sony side so we are unable to test them.
"Also the game is out in the US only so tests will be done at our Warner office, our UK office can't test yet sadly."
Some fans have found they can avoid the error message by disconnecting their consoles from the internet.