Three types of dreams in which Sat Guru appears

(from "Om Swami: as we know him"):

There are three dream states in which Swami is known to appear. One is where He consciously visits those who have been calling out to Him for guidance or simply to quench a devotee's thirst for a vision of Him. The love and reverence of such devotees makes Swami appear to them. What makes these dreams distinct is that the devotee remembers each and every detail, as clearly as if it had happened in a wakeful state. It takes them a while to slip back into reality of their lives. Swami's presence lingers like a favorite fragrance from the past.

With the second state, devotees may have been constantly contemplating Swami. As their devotion grows, their own thoughts at times manifest in the form of Swami in their dreams. These dreams may contain other people and images, and He may appear in the background. These dreams are vague, abstract, and may or may not make sense to a devotee upon waking up.

Then there is a third dream state, which is brought about by the devotee's ardent desire to have a darshan of the master. In this case, the devotee may have never set eyes on Swami in person, but hearing His glories or having read about Him has developed a strong reverence for Him. As his or her desire to seek Swami becomes most compelling, one of Swami's companion energies may appear in his or her dream, bearing Swami's grace and showering blessings upon such devotee. One of the characteristics of such dreams is the extraordinary surge of devotion for the master that ensues.