We bought one of these printers 16 months ago along with some extra ink blocks, as you do.
I have just recently tried to add the spare blocks and am coming up against a constant "Remove unidentified X ink stick" message for all of them (replace X with a different colour for each). The inks are showing as the correct for the printer on the box.
After much searching and calling Xerox (who wanted £300 for an engineer callout! anyone know anyone more expensive?) I have only come across a "secret" firmware change to country codes or a start-card workaround
The seller is aware of this problem but can only point to Xerox as it is out of warranty.
The print quality of this printer is unbeatable but it would seem so is this message - anyone know of a fix?