Updating project from 4.2 to 4.3 gives errors and rebuilding a backup of the 4.2 one gives the SAME ERORS!

Hi, this is a very puzzling situation: I had an original project with a recent backup copy. I tried to switch the original project from 4.2 to 4.3 (is derivated from VehicleGame), and that gave me so many errors to solve with my little C++ knowleade, so I went on working with the backup copy, and making it evolve (I’ve for example been able to package it without problem), but when opening today its VS solution to add a thing I first of all just rebuilt it (before changing anything) I got the same errors than in the original copy when I tried to move from 4.2 to 4.3!

How is this possible? Any chances to get my backup copy working again without having to deal with the tons of erros? Trying to switch it back to 4.2 doesn’t work at all. Any help would be apreciated.

Solved it: I updated VS 2013 Express, Generated new Visual Studio project files right-clicking on the uproject file and Rebuilt the solution in VS. Now it gives no errors.