there is a huge range of different challenges that project managers could face. Since a lot have been mentioned, and I have read other posts, a major unforgotten challenge was mentioned in one of the other posts. The challenge is having members of a team that don’t take their responsibility and acting unprofessionally. Dealing with a team member who plays a major role in the project but doesn’t take it seriously can be very challenging and would delay the entire project as a consequence if not dealt with it fast and in an assertive way.