Description
The game divides its story into DNA sequences, with each sequence containing a different mission taken from the memories of Desmond's ancestors. If you complete DNA Sequence 11 and turn off the game before entering the next DNA sequence, you'll start in the warehouse section of the modern-day assassin's hideout the next time you power up the game. Except Desmond's fellow assassins will be nowhere to be found, and there's no way for him to exit the warehouse or to reenter the Animus machine.
Glitch Environment
If you explore the warehouse, you'll find a section of wall that you can jump through, but doing so only causes you to land in water. You can swim around and continue to explore underwater, except you still won't be able to find an escape route. You won't even be able to make your way back into the warehouse. The water provides little more than a momentary distraction from a hopeless situation.
Solution
If you fall victim to the glitch, the only solution is to power off and restart the game, costing you hours of play and untold frustration. The easiest way to prevent the glitch is to not turn off the game after completing DNA Sequence 11. Simply continue on into the next DNA sequence before saving and shutting off the game. Of course, players unaware of the glitch only avoid it through dumb luck.
Patch
In December 2009, Ubisoft responded to public outcry over the warehouse glitch and released a downloadable patch to correct the problem. Once installed, the patch allows players to quit the game after DNA Sequence 11 without getting stuck in the warehouse upon resumption. The patch also corrects several other game bugs and glitches, including unpredictable game crashes and animation anomalies. The patch even provides sound enhancement through support of 5.1 LPCM.