If the milk in the pitcher is 'boiling over' or flowing over the edge while the Moose is steaming, ask yourself this: 

Is anything touching the pitcher holder while steaming? 

The pitcher holder acts as a weighing scale, telling the Moose exactly how much mi*lk you're about to steam. If you put a Moose hanky, barista towel or something else on or up against the pitcher holder while steaming, this could influence weight/amount measurement and confuses the Moose.  

Is the pitcher handle directed towards the Moose eye?

The Moose eye is measuring the temperature of the pitcher, just like your hands measure it when steaming manually. If the pitcher handle is directed towards the Moose eye, it's measuring the temperature of the handle and not your pitcher. This confuses the Moose. 

Is it one particular smart pitcher which overflows?

Check the status of your pitcher. If the coloured coating has come off for some reason, correct temperature measurement can be hindered. How to take care of smart Moose pitchers. 

Are there several pitchers which overflow?

If an overflow problem would occur with several smart pitchers, be sure the calibrating procedure when switching on the device was done correctly. Learn how to start up Perfect Moose correctly (calibration procedure).

Is there something going on with the boiler of your espressomachine?

When the boiler pressure from your espresso machine is too high, it could transfer too much pressure to Perfect Moose Greg. The boiler should provide a constant pressure between 1.3 and 1.4 bar (maximum allowed = 1.5 bar). Pressure variations outside the prescribed range can affect microfoam qualityUse a boiler for which Perfect Moose Greg is the only load.

Is the nozzle of the steam wand in the correct position?

Never turn or remove the nozzle of the steam wand and always leave it in the original position. Turning the nozzle could end up in poor quality microfoam. Check the right position of the nozzle.

Are the openings in the steam nozzle blocked?

Be sure to always flush and wipe after a steaming cycle so the nozzle doesn't get blocked. When the tiny openings in the nozzle are filled up, clear the openings with milk frother cleaning liquid.

Was milk added to the pitcher after the pitcher had already been fitted onto the pitcher holder? 

Never add milk or alternatives during a steaming cycle. Can I add milk or liquid during a steaming cycle?