It's not possible to compile a project; Podfile.lock no such file or directory

Step 1

I downloaded the Xcode 8.3 old version and defined it and Toolchains menu option as well but before, I run a fell commands on console:

Define the Xcode version:

~$ sudo xcode-select --switch /Applications/Xcode\ 8.3.app

And now you can prove the Swift configurated:

$ swift -version
Apple Swift version 3.0 (swift-3.0-RELEASE)
Target: x86_64-apple-macosx10.9

I run pod clean and pod install and it's ok.

The step two of the problem is on No such module PopupDialog on Swift3