'ld: file not found' after changing product name in Xcode

Question

I was working on my application and i started out with a really bad name. So i decided to change it. I did that like this.

At the top right corner i simply changed the name to what i want. and then i started getting the error as you can see there. Reveal in Log shows these details:

The main error says:

ld: file not found: /Users/.../XCode/DerivedData/...

Answer 1

Go to edit scheme as shown below.

then uncheck all other targets except your main target under build tab.

Answer 2

Real Issue

After changing the PRODUCT_NAME (as seen in the question) the erroneous reference to Host Application is the real cause of the issue.

Just select your Tests-Target and under the General-Tab select your updated Host Application.

Afterwards, building the project will work.