It happens in new Xcode7 beta:
CompileAssetCatalog /Users/admin/Library/Developer/Xcode/DerivedData/InstaAd-ddgdnbxlpxipirebpndfmgrxspel/Build/Products/Debug-iph
For all beta versions of Xcode you should go to Preferences->Locations and make sure that the command line tools point to the right version & that the Derived data and Archives point in a different folder that stable Xcode is