How to fix missing link after renaming a blueprint

Hi All,

I just move from another engine (cocos2d-x) and try using Unreal 4 (4.9.2).
I try to follow the tutorial “Endless Runner with Blueprints” and got a problem

I create a new project from Third Person template. There is an actor named ThirdPersonCharacter which does not match with the one in video.
So I rename it to RunCharacter but later found that I cannot open another blueprint inside Map folder.
I close and reopen the project. The system mentioned there is missing link on the project and I still cannot open that blueprint.

May I know how to fix it? Thank you