Recently I’ve come across this error a couple of times when running builds that exeucte unit tests using Test containers: API restriction: The assembly 'file:///C:\Builds\<path... has already loaded from a different location. It cannot be loaded from a new location within the same appdomain. Every time I’ve got this error, the project has been a web application, and the path to the assembly points down to the _PublishedWebsites directory that is created beneath the Binaries folder...