Possible Cause #1:
The humidity level or fan speed is set too high

Solution:
Reduce the humidity level or the fan speed

 

Possible Cause #2:
Water tank is not properly attached

Solution:
Make sure the water tank is properly attached to the base

Possible Cause #3:
Condensation built up from mist or from fan or A/C blowing the mist down

Solution: 
Move humidifier further away from wind/air outlet