We build TestFlight/App Store builds of our app through Xcode Cloud. Our app uses Metal shaders so we install the Metal toolchain through a ci_pre_xcodebuild.sh script which simply runs:
xcodebuild -downloadComponent metalToolchain
in our Xcode Cloud builds.
This has been working well for us for the last 6 months or so, but since yesterday (March 5) we have been seeing consistent failures when running this script in our Xcode Cloud builds:
Beginning asset download...
2026-03-06 04:14:34.727 xcodebuild[13315:58523] Writing error result bundle to /var/folders/6h/_32gb9js77g6c54h3q7g6q1h0000gn/T/ResultBundle_2026-06-03_04-14-0034.xcresult
xcodebuild: error: Failed fetching catalog for assetType (com.apple.MobileAsset.MetalToolchain), serverParameters ({
RequestedBuild = 17C7003j;
})
Prior to Mar 5 it looks like the toolchain image which was being downloaded/installed was 17C519 but this has now changed to 17C7003j.
We haven't changed anything with our Xcode Cloud workflow setup, and the same macOS/Xcode images are being used for the workflow runs (macOS Tahoe 26.2 (25C56) and Xcode 26.3 (17C529) respectively) now as when our builds were succeeding a few days ago.
What's the best way to resolve this issue? Looks like we can't even pass an image identifier to xcodebuild -downloadComponent so we're a bit stuck here.