Microsoft's new Xbox 360 disc format is incompatible with what the company describes as "a very small number" of machines.
The issue was discovered as part of the recent US beta in which the new discs were tested.
One Kotaku reader then received a surprise email from Microsoft stating that they had detected over Xbox Live that his machine (and 60GB Pro from 2009) would not work with the new discs.
However, much to the reader's surprise, Microsoft has offered to swap his console for a brand new Xbox 360 S and a year's free access to Xbox Live.
Microsoft will be rolling out an official Xbox 360 firmware upgrade from tomorrow that will allow for the introduction of the new disc format.