ld: library not found for -lGoogleToolboxForMac

I was also getting this exception:

It fixed after opening the /platform/ios folder in Xcode instead of /platform/ios/MyApp.xcodeproj file.

I got the same error and it was fixed just by opening the project from the .xcworkspace file instead of the .xcodeproj.

I change my pod file to following code and re-install pod. It installed all necessary files for GoogleToolboxForMac.

# Uncomment the next line to define a global platform for your project
platform :ios, '9.0'
target 'ProductName' do

  # Uncomment the next line if you're using Swift or would like to use dynamic frameworks
  # use_frameworks!

pod 'Firebase/Core'
pod 'Firebase/Messaging'
pod 'GoogleToolboxForMac', '~> 2.1'

end

After Installing pod

1) Change Scheme to Generic iOS Device and Build.

2) After build success you can see libGoogleToolboxForMac.a file in black colour instead of red.

3) Now select Device and run build on iDevice. Follow screenshot.

Or you can have build library libGoogleToolboxForMac.a