I’ve filed a report via Feedback Assistant: FB18047963. The report includes the linker snapshot and full Xcode build output from when the issue occurred.

Hi Ed, Thanks for your follow-up. When building with Xcode 16, the project compiles successfully with the -ld_classic flag. If we remove the flag, we get duplicate symbols errors. Our project includes multiple internal libraries, and some of them currently contain overlapping symbols. This isn’t something we can resolve quickly, so for now, we’re relying on -ld_classic for compatibility. We see the same issue when building with Xcode 16.2 beta (Build 16C5050e). Removing the -ld_classic flag also results in duplicate symbol errors, just like with Xcode 16.0. The libraries contain both iOS and iOS Simulator architectures. Our primary target platform is iOS, built for arm64. We’ll work on producing a minimal reproducible example and file a bug report. I’ll post the Feedback Assistant number here once that’s done. Best regards, ZWZ

We also encountered a similar issue on iOS 16.4.1, where the creation of AudioUnit failed and returned an error code: 268451843