Editor crashes at 71% when loading a specific project

I had just finished making new c++ classes when my editor crashed. From here on out every single time I try to load my project it crashes at 71%. I commented every change I made in the code and put it back to the way it was however my editor still crashes on load.

If it matters I was trying to cast a AController into a APlayerController then use ClientSetViewTarget() function when it crashed.

Okay, So i think what my problem was that I was trying to access private variables withing the engine code. I had to delete my intermediate and build folders and rebuild them then it started to work again.

What does that mean delete the intermediate? Build folders again? How do I do either of those things and what does it even mean

In the folder of your project (where your .uproject file is), there are two folders called “Intermediate” and “Binaries”. Delete them and Unreal will ask you to re-build when you open the project.

Just to say that this half worked for me. I got into a state where the uproject would crash on 71% and the sln opened with unloaded project file which would not reload because the vcxproj files were deleted and the uproject would not build them again successfully.
So, what I did was manually open the files with notepad++ (the offending cpp and header), manually comment out the offending lines (my most recent experimental additions) and then, rebuild the visual studio files. This time the build worked so I could now open visual studio with the project files loaded.
Did a build in visual studio which succeeded and then launched (- i.e. ctrl+F5) from visual studio. But, for some reason the startup project had changed to blank project so all I got was a quick flash of a command prompt type window and then nothing. Changed the startup project back to ue4 in visual studio and re-launch
And we all lived happily ever after.