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.
Yes, it is confirmed that the Prophet said: "The person who reads the whole Qur'an in less than three days does not grasp its meaning." We draw the attention of the questioner that the narration does not state that "It is not permissible to finish reading the Qur'an...", but the narration means that whoever reads the whole Qur'aan in less than three days does not understand its meaning, so this does not mean that he will not get the reward of the recitation of the Qur'aan. He will get the reward if he correctly reads it with proper pronunciation, as the Prophet said: "If anyone recites a letter from Allaah's Book he will be credited with a good deed, and a good deed gets a tenfold reward. I do not say that Alif-Lam-Mim is one letter, but Alif is a letter, Lam is a letter and Mim is a letter." [At-Tirmithi] So the narration means that whoever reads the whole Qur'aan in less than three days does not understand it but still gets the reward of reading it.
Allaah knows best.