Bethesda Softworks hopes to roll out a patch for Oblivion expansion Shivering Isles on Monday that will finally sort out the "formID" bug that's crippled the game for some dedicated players.
The bug, which has already been patched to some extent on the PC, renders the expansion unplayable on both formats after an extended period of time (between 50 and 120 hours on the PC, depending on your frame-rate, and between 75 and 150 hours on Xbox 360 depending on your play habits).
It has to do with the way the game identifies objects in the world. The simple version is that the game eventually runs out of identification numbers (formIDs) for things, confusing the way it manages system memory, corrupting data and failing to register objects when you save your progress.
For a more exhaustive rundown of what happens, check out the game's unofficial Wiki.
Anyway, the good news is that a patch is due on Monday, 30th April. "This will include the final update for PC, as well as the update for the 360 available through Xbox Live. This is a worldwide patch," Bethesda's community manager said on the developer's official forum. "Again, this is our target date, so hopefully all will go well in preparation for uploading these."
In the meantime, PC owners can make use of several unofficial tools listed on the unofficial Wiki, or grab Bethesda's official beta patch, providing you're okay with the consequences.
Or, you could read our Shivering Isles review to see what we make of the bits of the game that work. Which, to be fair, is most of it. Keep an eye on the Bethesda forums for updates on the patch's progress.