DIAGNOSIS Air trapped in the internal pump or heating tube, or severe mineral scale causing the pump to labor.
FIX Run several water-only brew cycles (no K-Cup) to purge air from the system. Use the 6oz setting for fastest cycling. The noise should diminish after 2-3 cycles.
IF THAT DIDN'T WORK The pump is failing due to scale. Descale the machine. If the screeching persists after descaling, the pump is likely damaged and requires replacement.
HEADS UP Always ensure the water reservoir is seated before starting a brew. An improperly seated reservoir introduces air into the system, causing pump cavitation and noise.