Abstract: A process for operating a hydraulic machine, especially a hydro-turbine, includes the step of detecting an actual machine state during operation of the machine by ascertaining operating data. The ascertained operating data includes flow through the turbine (if present), effective and reactive power fed into the electric mains, guide vane opening, pressure before the machine and at the suction pipe exit, headwater level, and tailwater level. The method further includes the step of processing at least one state characteristic values of a first cavitation characteristic value (indicative of cavitation intensity), a second cavitation characteristic value (indicative of an abrupt rise in cavitation manifestations), vibration characteristic values, suction pipe pressure, sand concentration, air pressure, water temperature, and generator temperature (for example winding temperature).