# Building for iOS results in error: clang: error: linker command failed

**URL:** <https://forums.unrealengine.com/t/building-for-ios-results-in-error-clang-error-linker-command-failed/104932>\
**Category:** Mobile\
**Tags:** unreal-engine, iOS\
**Created:** [January 12, 2018, 9:26am UTC](https://forums.unrealengine.com/t/building-for-ios-results-in-error-clang-error-linker-command-failed/104932 "2018-01-12T09:26:01Z")\
**Posts on this page:** 1\
**Showing post:** 4

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**Author:** ![RiskNerd](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@RiskNerd](https://forums.unrealengine.com/u/RiskNerd)\
**Post date:** [August 14, 2025, 7:42pm UTC](https://forums.unrealengine.com/t/building-for-ios-results-in-error-clang-error-linker-command-failed/104932/4 "2025-08-14T19:42:36Z")

</div>

The problem here turns out to be that MacOS was installed on a case-sensitive filesystem.

The iAd Framework (note the camelCase with uppercase A and lowercase d) still exists in the iOS SDK at this location:

```auto
% ls /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS.sdk/System/Library/Frameworks/iAd.framework 
Headers	iAd.tbd	Modules

```

However, UE 5.6.1 and all previous releases contain build instructions to link with the iAD framework.

The same problem prevents linking with the CloudKit framework, because UE tries to link with a different framework named “Cloudkit” (lowercase k) which, on a case-insensitive filesystem like APFS isn’t viewed as a different path.

NOTE: my installation of UE 5.6.1 uses an APFS case-insensitive Volume, which I suspect will work fine now that I know where to look for dependencies during the build process that might be case sensitive. Providing the required frameworks or library files in a subdirectory created under my APFS Volume and adding -F/Volumes/UEBuild to my linker settings lets me continue the build process to find out if some other case-sensitive build step is going to fail next. I don’t have the iOS App building completely yet, now I need to pay Apple for a developer account so I can use code signing.

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