All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger. We ask Allaah to exalt his mention as well as that of his family and all his companions.
It is known that Allaah's Names are derived from His Book or mentioned in the authentic Sunnah of the Prophet . The Name Ar-Rasheed (which implies the Guide to the right path) is not mentioned in the Qur'an. However, there is a narration reported by At-Tirmithi in which the Prophet said: "Indeed, Allaah has ninety-nine Names…", and the Name Ar-Rasheed is mentioned in the narration. This narration is classified by the scholars of Hadeeth as weak.
To conclude, Ar-Rasheed, is not one of the beautiful Names of Allaah because it is neither mentioned in the Qur'an nor in the correct Sunnah of the Prophet . The Names and attributes of Allaah are only known by the revelation or from the authentic Sunnah.
Allaah knows best.