just press later ;)
@orassr Doesn't work, it ask to set it to use a legacy swift version. I change the option to use a Legacy Swift Version, then I get 625 errors instantly pop up.

I got the same issue after run "pod install" for installing other frameworks yesterday. Problem solved now. Below is what I did.
pod update to update to Alamofire 4.0.1
Most helpful comment
Solution
pod updateto update to Alamofire 4.0.1