There have been a lot of rumors circulating about serious bugs in The Elder Scrolls IV: Oblivion´s Shivering Isles add-on and Guitar Hero 2´s update. These rumors have now been verified.
Bethesda has confirmed that there really is a bug in the Shivering Isles´ PC and Xbox 360 versions, that makes playing the game virtually impossible after 50120 hours of gameplay, starting from the add-on´s download and installation. The bug causes, for instance, disappearance of some items. Because of lower frame rate on Xbox 360, the error´s appearance may take as long as 80150 hours. Bethesda encourages PC players to copy their save just in case and avoid playing before an official update is released. An unofficial update is already available. Xbox 360 players are also recommended to avoid playing, or to play with a new character.
Guitar Hero 2´s recent update to fix the problems of the Whammy bar has caused even more serious problems that allegedly can even make the whole Xbox 360 console break down for at least some users. RedOctane has confirmed that this error is real and that they are currently investigating the issue the bug is said to affect only few players. The wait for this update´s update should not be too long, but that is unlikely to console the owners of already broken machines.
If you haven´t downloaded the Guitar Hero 2 update yet, good, you should leave it for now and play the game without signing in to Xbox Live. Oblivion, on the other hand, can likely be played without problems for at least 50 hours before the update arrives.