BadImageFormatException debugging web site running in x64 mode

Question

There are a lot of questions on this forum about the BadImageFormatException, but none quite matches my issue.

I have a solution containing several proj

Answer 1

In my case, for Visual Studio 2019, there was no need to edit the registry manually. I followed the instructions found here.

When you launch a web project in Visual Studio, by default it uses the 32-bit version of IIS Express. To change that you can enable the 64-bit version through Options.

So, head to:

Tools --> Options --> Project and Solutions --> Web Projects

Check the option “Use the 64 bit version of IIS Express for web sites and projects”

This fixed it for me.