Added a new pod target to a very old project. got that error.
heres my steps that worked.
I had to uninstall cocoapods completely
it removed about 5 old versions
and wiped the whole workspace file
sudo gem uninstall cocoapods --all
sudo gem install cocoapods
//delete Derived Data - you could try just deleting the folder for your project but project only built when I wiped it all
rm -rf ~/Library/Developer/Xcode/DerivedData/
rm -rf ~/Library/Caches/CocoaPods/
pod deintegrate
//delete the *.workspace file
pod update
open workspace
Topic:
Developer Tools & Services
SubTopic:
Xcode
Tags: