What is the state of a Zen disciples mind prior to a Satori?
It's a state known as Great Doubt, "dai-gidan" (Japanese) or "dayituan" (Chinese):


  In Ch'an and Zen practice, this represents a highly intense doubt about everything one thinks to be true, including the efficacy of Zen practice itself. (Oxfordreference.com)


For more information, please see the following question: How does the 'Great Doubt' compare to doubt.