Hello @rowan_bradley: are you sure it's "***Tray full***" and not " ***Missing tray***"? As far as I remember the message ***Tray full*** ist generated by software, this means the machine only counts how many cups have been produced after the last emptying. This works normally smoothly, but perhaps it does not register, when opened. I think, it should probably be a fault in the microswitch on the drip tray. Fortunately, we have a [guide|131913|guide] for this. Replace the microswitch Cherry D44X , its cheap. Good luck and tell us, if this was the solution.