unity 5.2.4 iOS build error ,iOS build error

Failed running /Applications/Unity/Unity.app/Contents/Frameworks/Tools/UnusedByteCodeStripper2/UnusedBytecodeStripper2.exe -out "/Volumes/Unity/unityTest/Temp/StagingArea/Data/Managed/tempStrip" -l none -c link -x "/Applications/Unity/Unity.app/Contents/Frameworks/Tools/UnusedByteCodeStripper/native_link.xml" -f "/Applications/Unity/Unity.app/Contents/Frameworks/il2cpp/LinkerDescriptors" -x "/Volumes/Unity/unityTest/Temp/StagingArea/Data/Managed/../platform_native_link.xml" -x "/Volumes/Unity/unityTest/Temp/StagingArea/Data/methods_pointedto_by_uievents.xml" -d "/Volumes/Unity/unityTest/Temp/StagingArea/Data/Managed" stdout: Fatal error in Mono CIL Linker System.ArgumentException: Unable to find the file for the assembly named 'UnityEngine'. Should this assembly be in the project? ---> Mono.Cecil.AssemblyResolutionException: Failed to resolve assembly: 'UnityEngine, Version=0.0.0.0, Culture=neutral, PublicKeyToken=null' at Mono.Linker.LinkContext.Resolve (IMetadataScope scope) [0x00000] in :0 at Mono.Linker.Steps.ResolveFromXmlStep.GetAssembly (Mono.Linker.LinkContext context, System.String assemblyName) [0x00000] in :0 at Mono.Linker.Steps.ResolveFromXmlStep.ProcessAssemblies (Mono.Linker.LinkContext context, System.Xml.XPath.XPathNodeIterator iterator) [0x00000] in :0 --- End of inner exception stack trace --- at Mono.Linker.Steps.ResolveFromXmlStep.ProcessAssemblies (Mono.Linker.LinkContext context, System.Xml.XPath.XPathNodeIterator iterator) [0x00000] in :0 at Mono.Linker.Steps.ResolveFromXmlStep.Process () [0x00000] in :0 at Mono.Linker.Steps.BaseStep.Process (Mono.Linker.LinkContext context) [0x00000] in :0 at Mono.Linker.Pipeline.Process (Mono.Linker.LinkContext context) [0x00000] in :0 at Mono.Linker.Driver.Run () [0x00000] in :0 at Mono.Linker.Driver.RunDriverWithErrorHandling (Mono.Linker.Driver driver) [0x00000] in :0 at Mono.Linker.Driver.RunDriver (Mono.Linker.Driver driver) [0x00000] in :0 stderr: UnityEngine.Debug:LogError(Object) UnityEditorInternal.Runner:RunManagedProgram(String, String, String, CompilerOutputParserBase) (at /Users/builduser/buildslave/unity/build/Editor/Mono/BuildPipeline/Il2Cpp/IL2CPPUtils.cs:68) UnityEditorInternal.AssemblyStripper:RunAssemblyLinker(IEnumerable`1, String&, String&, String, String) (at /Users/builduser/buildslave/unity/build/Editor/Mono/BuildPipeline/Il2Cpp/IL2CPPUtils.cs:199) UnityEditorInternal.AssemblyStripper:StripAssembliesTo(String, String, String&, String&, String, String, IEnumerable`1) (at /Users/builduser/buildslave/unity/build/Editor/Mono/BuildPipeline/Il2Cpp/IL2CPPUtils.cs:192) UnityEditorInternal.AssemblyStripper:Strip(String, String, String&, String&, String, String, IEnumerable`1) (at /Users/builduser/buildslave/unity/build/Editor/Mono/BuildPipeline/Il2Cpp/IL2CPPUtils.cs:143) UnityEditorInternal.AssemblyStripper:Strip(String[], String[], String, String, String&, String&, String, String, IEnumerable`1) (at /Users/builduser/buildslave/unity/build/Editor/Mono/BuildPipeline/Il2Cpp/IL2CPPUtils.cs:123) UnityEditorInternal.IL2CPPBuilder:RunAssemblyStripper(IEnumerable, String, String[], String[], String) (at /Users/builduser/buildslave/unity/build/Editor/Mono/BuildPipeline/Il2Cpp/IL2CPPUtils.cs:465) UnityEditorInternal.IL2CPPBuilder:StripAssemblies(IEnumerable`1, String) (at /Users/builduser/buildslave/unity/build/Editor/Mono/BuildPipeline/Il2Cpp/IL2CPPUtils.cs:438) UnityEditorInternal.IL2CPPBuilder:Run() (at /Users/builduser/buildslave/unity/build/Editor/Mono/BuildPipeline/Il2Cpp/IL2CPPUtils.cs:299) UnityEditorInternal.IL2CPPUtils:RunIl2Cpp(String, String, IIl2CppPlatformProvider, Action`1, RuntimeClassRegistry) (at /Users/builduser/buildslave/unity/build/Editor/Mono/BuildPipeline/Il2Cpp/IL2CPPUtils.cs:218) UnityEditor.BuildPlayerWindow:BuildPlayerAndRun(),Failed running /Applications/Unity/Unity.app/Contents/Frameworks/Tools/UnusedByteCodeStripper2/UnusedBytecodeStripper2.exe -out "/Volumes/Unity/unityTest/Temp/StagingArea/Data/Managed/tempStrip" -l none -c link -x "/Applications/Unity/Unity.app/Contents/Frameworks/Tools/UnusedByteCodeStripper/native_link.xml" -f "/Applications/Unity/Unity.app/Contents/Frameworks/il2cpp/LinkerDescriptors" -x "/Volumes/Unity/unityTest/Temp/StagingArea/Data/Managed/../platform_native_link.xml" -x "/Volumes/Unity/unityTest/Temp/StagingArea/Data/methods_pointedto_by_uievents.xml" -d "/Volumes/Unity/unityTest/Temp/StagingArea/Data/Managed" stdout: Fatal error in Mono CIL Linker System.ArgumentException: Unable to find the file for the assembly named 'UnityEngine'. Should this assembly be in the project? ---> Mono.Cecil.AssemblyResolutionException: Failed to resolve assembly: 'UnityEngine, Version=0.0.0.0, Culture=neutral, PublicKeyToken=null' at Mono.Linker.LinkContext.Resolve (IMetadataScope scope) [0x00000] in :0 at Mono.Linker.Steps.ResolveFromXmlStep.GetAssembly (Mono.Linker.LinkContext context, System.String assemblyName) [0x00000] in :0 at Mono.Linker.Steps.ResolveFromXmlStep.ProcessAssemblies (Mono.Linker.LinkContext context, System.Xml.XPath.XPathNodeIterator iterator) [0x00000] in :0 --- End of inner exception stack trace --- at Mono.Linker.Steps.ResolveFromXmlStep.ProcessAssemblies (Mono.Linker.LinkContext context, System.Xml.XPath.XPathNodeIterator iterator) [0x00000] in :0 at Mono.Linker.Steps.ResolveFromXmlStep.Process () [0x00000] in :0 at Mono.Linker.Steps.BaseStep.Process (Mono.Linker.LinkContext context) [0x00000] in :0 at Mono.Linker.Pipeline.Process (Mono.Linker.LinkContext context) [0x00000] in :0 at Mono.Linker.Driver.Run () [0x00000] in :0 at Mono.Linker.Driver.RunDriverWithErrorHandling (Mono.Linker.Driver driver) [0x00000] in :0 at Mono.Linker.Driver.RunDriver (Mono.Linker.Driver driver) [0x00000] in :0 stderr: UnityEngine.Debug:LogError(Object) UnityEditorInternal.Runner:RunManagedProgram(String, String, String, CompilerOutputParserBase) (at /Users/builduser/buildslave/unity/build/Editor/Mono/BuildPipeline/Il2Cpp/IL2CPPUtils.cs:68) UnityEditorInternal.AssemblyStripper:RunAssemblyLinker(IEnumerable`1, String&, String&, String, String) (at /Users/builduser/buildslave/unity/build/Editor/Mono/BuildPipeline/Il2Cpp/IL2CPPUtils.cs:199) UnityEditorInternal.AssemblyStripper:StripAssembliesTo(String, String, String&, String&, String, String, IEnumerable`1) (at /Users/builduser/buildslave/unity/build/Editor/Mono/BuildPipeline/Il2Cpp/IL2CPPUtils.cs:192) UnityEditorInternal.AssemblyStripper:Strip(String, String, String&, String&, String, String, IEnumerable`1) (at /Users/builduser/buildslave/unity/build/Editor/Mono/BuildPipeline/Il2Cpp/IL2CPPUtils.cs:143) UnityEditorInternal.AssemblyStripper:Strip(String[], String[], String, String, String&, String&, String, String, IEnumerable`1) (at /Users/builduser/buildslave/unity/build/Editor/Mono/BuildPipeline/Il2Cpp/IL2CPPUtils.cs:123) UnityEditorInternal.IL2CPPBuilder:RunAssemblyStripper(IEnumerable, String, String[], String[], String) (at /Users/builduser/buildslave/unity/build/Editor/Mono/BuildPipeline/Il2Cpp/IL2CPPUtils.cs:465) UnityEditorInternal.IL2CPPBuilder:StripAssemblies(IEnumerable`1, String) (at /Users/builduser/buildslave/unity/build/Editor/Mono/BuildPipeline/Il2Cpp/IL2CPPUtils.cs:438) UnityEditorInternal.IL2CPPBuilder:Run() (at /Users/builduser/buildslave/unity/build/Editor/Mono/BuildPipeline/Il2Cpp/IL2CPPUtils.cs:299) UnityEditorInternal.IL2CPPUtils:RunIl2Cpp(String, String, IIl2CppPlatformProvider, Action`1, RuntimeClassRegistry) (at /Users/builduser/buildslave/unity/build/Editor/Mono/BuildPipeline/Il2Cpp/IL2CPPUtils.cs:218) UnityEditor.BuildPlayerWindow:BuildPlayerAndRun()