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

Go to edit scheme as shown below.

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

I recently got this error under different circumstances. Running Ionic, updating my ios platform from 3.8.0 to 4.0.1 I discovered this error.

I had to disable bitcode in my app.

To do this, click your top level app icon in the file structure. In the main window, click the header build settings. In the search bar, type bit (or bitcode) and you should see enable bit code beneath

I had disabled it before, but I'm guessing that updating the ios platform enables bitcode so it needed to be disabled again.