When Saturn transits through the 1st, 2nd& 12thhouse from the natal moon a condition known as ‘Sade Sati’ occurs:
Saturn takes two and half years to travel through one sign or in other words it takes seven and half years to cross all the three signs.It is a common belief that sade sati brings dissatisfaction, dispute, depression, differences and considered as highly inauspicious.  This is because Saturn is considered as most maleficent planet amongst astrologers, but it may not be so.

It doesn’t affect everyone in the same fashion as it does to some. It is certain that whenever Saturn comes along people in general experience some tensions in their life, but such should be considered as a matter of dire tensions. It is not a denial of success rather an adducer of burden. Known examples show that people have achieved heights during this period. PanditJawaharLal Nehru became the Prime Minister of India during the sade sati period. 

Conclusion:

However, as per the Nadi astrology Dasha, Bhukti and Antra should be positive for an event.  If all three are good then it shall be safe to assume that Saturn shall do no harm. A single planet alone cannot be considered a malefic factor unless it is backed by atleast three to four negative planets.