[citation][nom]random_guy417[/nom]1) Why is Microsoft working on this issue? It seems to have been created by Bungie, not Microsoft. Bungie should be fixing this issue with their game.2) Why is everyone dissing Microsoft? They are not the ones that made the game. The developer is responsible for making sure their games work on all 360s or advertising that it may not work for some configuration.[/citation]
The fact that MS is working on it implies that it might be an issue with some core functionality of the XBox360, not a problem with Bungie's code. e.g. Halo might be querying the system to see if there is a storage device present, and sometimes they're getting the wrong answer due to a bug in the XB360 firmware/OS. Bungie couldn't really fix something like that. (But that's just speculation; MS might also be helping Bungie fix a bug in their code simply because Halo is such a high-profile title.)
As for not catching it in testing? It's harder than you would think. I'm pretty sure that they at least ran it on every type of stock XB360. But it wouldn't surprise me if they did most of their testing on systems with internal hard drives. While in development, they would probably want to load new builds of the game over the network onto the hard disk and run it from there, rather than having to burn copies to DVDs.
If the issue is something that only happens in one type of configuration, and also needs some other unusual set of circumstances, AND maybe only happens in certain game modes, I can see how you might not run into it during testing. It's unlikely that Bungie extensively tested every possible combination of multiplayer game modes with every possible combination of XB360 hardware configurations, especially if they knew that their code shouldn't behave any differently. I'm sure they were more concerned with testing the game engine itself and things like their netcode, not how they query the storage devices.