“An attempt was made to load a program with an incorrect format” even when the platforms are the same

Question

I\'m calling functions from a 32-bit unmanaged DLL on a 64-bit system. What I get is:

BadImageFormatException: An attempt was made to load a program w

Answer 1

If you are using Any CPU, you might encounter this issue if the Prefer 32-bit option is checked:

Make sure you uncheck this option in the project's property's Build tab!