Convert UE 4.7 project

I am trying to convert UE4.7 project to 4.8. I have been trying to right click on the “Unreal Engine Project File” and click on “Switch unreal versions” and rebuilt the project. After that I opened Visual Studio I rebuilt the code and trying to run the engine with it, but I am getting the folliwing error:

How can I fix it?

I’m sorry to ask this, but did you rebuild your project after the switch?

Of course, Sorry I did not mention this I will edit

Ok solved it, I had to turn the program to win64 and not 32. but why? Is it limit me? how can I build the program with 32 bit?