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.