XCode update on Mac OS breaks build process UE 5.6

Development Programming & Scripting
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1

I’m using an M2 mac for development and teaching - it is administered by my employer, and this morning an update was pushed out that updated XCode. I had to re-accept the license.

this is what i have now:

wsack@cast-wsackml lab01 % clang -v
Apple clang version 17.0.0 (clang-1700.3.19.1)
Target: arm64-apple-darwin24.6.0
Thread model: posix
InstalledDir: /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin
wsack@cast-wsackml lab01 %

When i went to build a project that had worked the day before, i got this error message:

/Users/wsack/Applications/UE_5.6/Engine/Build/BatchFiles/Mac/../../../Binaries/ThirdParty/DotNet/8.0.300/mac-arm64
Running dotnet Engine/Binaries/DotNET/UnrealBuildTool/UnrealBuildTool.dll DMS332Editor Mac Development /Users/wsack/Documents/Unreal Projects/DMS332/DMS332.uproject -waitmutex
Log file: /Users/wsack/Library/Application Support/Epic/UnrealBuildTool/Log.txt
Using ‘git status’ to determine working set for adaptive non-unity build (/Users/wsack/Documents/Unreal Projects/DMS332).
Invalidating makefile for DMS332Editor (ispc deleted)
Platform Mac is not a valid platform to build. Check that the SDK is installed properly and that you have the necessary platform support files (DataDrivenPlatformInfo.ini, SDK.json, etc).

Here is the relevant section of UnrealBuildTool/Log.txt

Skipping /Users/wsack/Applications/UE_5.6/Engine/Intermediate/Build/BuildRules/UE5Rules.dll: File is installedSkipping /Users/wsack/Applications/UE_5.6/Engine/Intermediate/Build/BuildRules/UE5ProgramRules.dll: File is installedUsing ‘git status’ to determine working set for adaptive non-unity build (/Users/wsack/Documents/Unreal Projects/DMS332)./Users/wsack/Applications/UE_5.6/Engine/Source/ThirdParty/Intel/ISPC/bin/Mac/ispc has been deleted since makefile was built.Invalidating makefile for DMS332Editor (ispc deleted)Platform Mac is not a valid platform to build. Check that the SDK is installed properly and that you have the necessary platform support files (DataDrivenPlatformInfo.ini, SDK.json, etc).BuildException: Platform Mac is not a valid platform to build. Check that the SDK is installed properly and that you have the necessary platform support files (DataDrivenPlatformInfo.ini, SDK.json, etc).at UnrealBuildTool.UEBuildTarget.Create(TargetDescriptor Descriptor, Boolean bSkipRulesCompile, Boolean bForceRulesCompile, Boolean bUsePrecompiled, UnrealIntermediateEnvironment IntermediateEnvironment, ILogger Logger)at UnrealBuildTool.UEBuildTarget.Create(TargetDescriptor Descriptor, BuildConfiguration BuildConfiguration, ILogger Logger)at UnrealBuildTool.BuildMode.CreateMakefileAsync(BuildConfiguration BuildConfiguration, TargetDescriptor TargetDescriptor, ISourceFileWorkingSet WorkingSet, ILogger Logger)at UnrealBuildTool.BuildMode.BuildAsync(List`1 TargetDescriptors, BuildConfiguration BuildConfiguration, ISourceFileWorkingSet WorkingSet, BuildOptions Options, FileReference WriteOutdatedActionsFile, ILogger Logger, Boolean bSkipPreBuildTargets, String ActionTypeFilter)at UnrealBuildTool.BuildMode.ExecuteAsync(CommandLineArguments Arguments, ILogger Logger)at UnrealBuildTool.UnrealBuildTool.Main(String ArgumentsArray)WriteFileIfChanged() wrote 0 changed files of 1 requested writes.

Timeline:[  0.000]  +0.340 Main0.087          [  0.087]  +0.080 Apply XmlConfig0.223          [  0.223]  +0.117 RegisterPlatforms[  0.340]  +2.218 BuildMode0.340          [  0.000]  +2.077 2.417          [  2.077]  +0.130 Creating MakeFile for DMS332Editor2.549          [  2.208]  +0.009 Saving caches[  2.569]  +0.000 TelemetryService.FlushEvents[  2.570]

Result: Failed (OtherCompilationError)Total execution time: 2.57 seconds

I don’t know what SDK this refers to. Is there someplace in the editor i have to change the clang version? Is it possible to fix this without rolling back the xcode version?

2

I am seeing something similar on 5.4.4 and hoping for a fix soon.

Rider will no longer generate the project. Digging into the logs shows this line:

Registering build platform: Mac - buildable: False

But little else.

I have attempted a lot of little fixes but none seem to work.

3

To get around this for now, I downloaded Xcode 16.4 by following the link from this index (which redirects to a link from apple). I extracted the .xip file (which just puts a single .app in the directory it’s extracted into), and then used xcode-select --switch /[target directory you extracted it to]/Xcode.app/Contents/Developer

I believe you can maintain the second installation until this issue is fixed, and go back to the default one if you need to using xcode-select.

1 Like
4

I’m on the same situation with my m2 mini which I use as a fully CI/CD to build all Apple platform package of my game.

Thanks @tdmann it’s work very well.

I hope that Epic publish an update quickly.

5

This is a great solution, though it does require root permission to run xcode-select and I can’t do it on my uni-owned lab computers … i’ll ask the admins if they’ll do it for me.

i’m wondering, while we’re here, if the Apple_SDK.json file has something to do with this? The contents of it in my 5.6 installation are:

{
    // Xcode versions

"MainVersion": "15.2",

"MinVersion": "15.2.0",

"MaxVersion": "16.9.0",

// !!!

// NOTE: If you update the MaxVersion, double check the AppleVersionToLLVMVersion array below!!!

// !!!



// The versions on Windows are iTunes versions

"MinVersion_Win64": "1100.0.0.0",

"MaxVersion_Win64": "8999.0",



// This is not a version range, but a mapping of Xcode clang versions to LLVM versions, for shared version checks with other clangs

// Version mapping can be found at 

// The first version is the first version that is using the second version source LLVM

"AppleVersionToLLVMVersions": [

"14.0.0-14.0.0", // Xcode 14.0 -> LLVM 14.0

"14.0.3-15.0.0", // Xcode 14.3 -> LLVM 15.0

"15.0.0-16.0.0", // Xcode 15.0 -> LLVM 16.0

"16.0.0-17.0.6", // Xcode 16.0 -> LLVM 17.0.6

    ],

}

is this line “MaxVersion”: “16.9.0” the one that’s causing it to break?

6

The same thing happens with Rider itself - after XCode upgrade, it can no longer load a project + it complains about the Unreal Link not being installed in the engine and it cannot install it.

Thanks to @tdmann for the fix, downgrading back to the previous major XCode version indeed helped.

I guess we have to wait until Unreal and Rider catch up with the new XCode. If someone has news re this, it would be great to know!