Xcode Version 6.1 (6A1030) - Apple Mach O-Linker Error - Building

Question

I upgraded my Xcode to the latest version: Version 6.1 (6A1030).
I use Swift language.
When I build my app, I have 25 issues:

Apple Mach-O Linker error

Undefined symbols for architecture i386:
"__TFE10FoundationCSo11NSPredicateCfMS0_Ft6formatSSGSaPSs11CVarArgType___GSqS0__", referenced from:
          __TFC19TestBentley_Network8EventDAO11updateEventfS0_FCS_5EventT_ in EventDAO.o
          __TFC19TestBentley_Network8EventDAO10deletEventfS0_FCS_5EventT_ in EventDAO.o
      "__TFE10FoundationCSo7NSArray8generatefS0_FT_CS_15NSFastGenerator", referenced from:
          __TFC19TestBentley_Network8EventDAO10deletEventfS0_FCS_5EventT_ in EventDAO.o
      "__TFE10FoundationCSo8NSString24convertFromStringLiteralfMDS0_FVSs12StaticStringDS0_", referenced from:
          __TFO19TestBentley_Network13NotificationsCfMS0_FT8rawValueCSo8NSString_GSqS0__ in Notifications.o
          __TFO19TestBentley_Network13Notificationsg8rawValueCSo8NSString in Notifications.o
          __TFC19TestBentley_Network30NetworkSearchPropositionButtoncfMS0_FT5coderCSo7NSCoder_S0_ in NetworkSearchPropositionButton.o
          __TFC19TestBentley_Network8HomeViewcfMS0_FT5frameVSC6CGRect9networkVCCS_21NetworkViewController9membersVCCS_21MembersViewController10servicesVCCS_22ServicesViewController8profilVCCS_20ProfilViewController8eventsVCCS_20EventsViewController_S0_ in HomeView.o
          __TFC19TestBentley_Network24EventsListViewControllercfMS0_FT_S0_ in EventsListViewController.o
          __TFC19TestBentley_Network8MenuViewcfMS0_FT5frameVSC6CGRect_S0_ in MenuView.o
          __TFC19TestBentley_Network29NetworkSearchPropositionsList18reloadPropositionsfS0_FGSqCSo8NSString_T_ in NetworkSearchPropositionsList.o
          ...
      "__TFE10FoundationSS19_bridgeToObjectiveCfSSFT_CSo8NSString", referenced from:

Answer 1

As usual when upgrading Xcode:

• Clean your build folder (Product -> (Alt key) -> Clean Build Folder)
• Clean project (Product -> Clean)
• Delete derived data
  • Xcode < 6.3: Window -> Organizer -> Delete derived data
  • Xcode >= 6.3: Window -> Projects (select project) -> Delete derived data

Then try to build your project again.