win32exception : invalid data when building for ios

im using unity 5.0.0f4 personal and mac osx 10.10.2 and xcode 6.1 every time i build for ios i got the following error:

Win32Exception: Invalid data System.Diagnostics.Process.Start_shell (System.Diagnostics.ProcessStartInfo startInfo, System.Diagnostics.Process process) System.Diagnostics.Process.Start_common (System.Diagnostics.ProcessStartInfo startInfo, System.Diagnostics.Process process) System.Diagnostics.Process.Start () (wrapper remoting-invoke-with-check) System.Diagnostics.Process:Start () UnityEditor.iOS.Utils.SymlinkFile (System.String src, System.String dst) UnityEditor.iOS.PostProcessiPhonePlayer.InstallXcodePlugin () UnityEditor.iOS.PostProcessiPhonePlayer.UpdateInstallLocation (UnityEditor.iOS.ProjectPaths paths, ScriptingImplementation backend, BuildOptions options, UnityEditor.iOS.IncludedFileList includedFiles) UnityEditor.iOS.PostProcessiPhonePlayer.PostProcess (UnityEditor.iOS.iOSBuildPostprocessor pp, BuildTarget target, System.String stagingAreaData, System.String stagingArea, System.String stagingAreaDataManaged, System.String playerPackage, System.String installPath, System.String companyName, System.String productName, BuildOptions options, UnityEditor.RuntimeClassRegistry usedClassRegistry) UnityEditor.iOS.iOSBuildPostprocessor.PostProcess (BuildPostProcessArgs args) UnityEditor.PostprocessBuildPlayer.Postprocess (BuildTarget target, System.String installPath, System.String companyName, System.String productName, Int32 width, Int32 height, System.String downloadWebplayerUrl, System.String manualDownloadWebplayerUrl, BuildOptions options, UnityEditor.RuntimeClassRegistry usedClassRegistry) (at /Users/builduser/buildslave/unity/build/Editor/Mono/BuildPipeline/PostprocessBuildPlayer.cs:316) UnityEditor.HostView:OnGUI()