Intellect can be said to interfere with the attainment of enlightenment when it leads to delusion. What is delusion? It is a belief based on something that is not true.
Again and again in recent months are people who are challenging the use of intellect and concepts in making progress on the spiritual journey. Fascinating! Turns out they are correct only when it results in delusion, but they don't know what the delusion is. Whether it's theirs or in many cases someone else's, they just don't know. Since it doesn't appear as delusion, they buy it, and seeing it as associated with failure to awaken they put down thinking and concepts in general. Aha!