I had built a new application using System.Data.Sqlite. When I run the application, I got an exception, System.BadImageFormatException.Well, I found I was using 64-bit version, because System.Data.Sqlite will call some unmanaged dlls. So, it still needs to be in 32-bit. After I changed to use 32-bit dll,then all goods. Or you can switch your build target to 64 bit and using 64 bit dlls.