Are you trying to build the Editor for Win32, or your project? The Editor can only be built for Win64, and if you try to build it for Win32 you should receive a message stating that UE4Editor does not support the Win32 platform.
If you are trying to build your project for Win32, then we will have to do some additional investigation.
You can not build the Development Editor - Win32 confifguration in Visual Studio. The UE Editor has to build on Win64. You can only build “Development/Shipping” with Win32 to package the game with Win32. It’s similar to Android and iOS Package