MetalToolchain download fails on macOS 26.2, build 17C48 catalog error

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nvazquez0602 OP

Created 4d

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Without this, I can't install/open Unreal Engine on my iMac OS 26.2 Tahoe.

I can't even download the Metal Toolchain in Xcode-Settings-Components. It fails every time.

when I try to open Unreal Engine, it says this:

Xcode Metal Compiler error: error: error: cannot execute tool 'metal' due to missing Metal Toolchain; use: xcodebuild -downloadComponent MetalToolchain

But every time I try to download Metal Toolchain in terminal, it says this:

xcodebuild: error: Failed fetching catalog for assetType (com.apple.MobileAsset.MetalToolchain), serverParameters ({ RequestedBuild = 17C48; })

% sudo xcode-select --reset xcrun -f metallib Password: xcrun: error: sh -c '/Applications/Xcode.app/Contents/Developer/usr/bin/xcodebuild -sdk /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk -find metallib 2> /dev/null' failed with exit code 17664: (null) (errno=No such file or directory) xcrun: error: unable to find utility "metallib", not a developer tool or in PATH

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DTS Engineer OP

Apple

1d

xcodebuild: error: Failed fetching catalog for assetType (com.apple.MobileAsset.MetalToolchain), serverParameters ({ RequestedBuild = 17C48; })

This can indicate a network-level error reaching Apple's servers. By chance, is your device or network managed by an IT department? I ask because some enterprises use the information in Use Apple products on enterprise networks to configure devices or the overall enterprise network to meet the needs of the enterprise, but that may be in conflict here with getting the Metal toolchain.

If you run the following commands in Terminal, what do you get as a result?

% curl -v https://gdmf.apple.com
% curl -v https://download.developer.apple.com
% curl -v https://devimages-cdn.apple.com

If you get an HTTP result (even if it's a 404), that's good, because it means your Mac could reach that server to get an HTTP code. But if you get a different message like a failure to connect, then that indicates something is interfering with your Mac's ability to reach Apple's services. Let me what result get you get!

— Ed Ford,  DTS Engineer

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