Xcode 16.2 throws an error in debug mode

The error message "Assertion failed: (reconstituted == accumulator), function setFixup64, file OutputFile.cpp, line 2975" typically occurs during the linking process in Xcode, and it suggests a mismatch in data during the compilation of your app. Here are some troubleshooting steps you can take to resolve this issue:

• Clean Build Folder:
  • Go to Product > Clean Build Folder (or press Shift + Command + K).
  • This will remove all the build artifacts and may resolve the issue if it's caused by corrupted files.
• Derived Data:
  • Delete the Derived Data folder.
  • Go to Finder, then press Shift + Command + G and enter ~/Library/Developer/Xcode/DerivedData/.
  • Move the Derived Data folder for your project to the Trash.
  • Restart Xcode and build your project again.
• Restart Xcode and Mac:
  • Sometimes, a simple restart can resolve temporary issues.
• Check for Dependencies:
  • Ensure that all your project's dependencies are up to date.
  • If you're using CocoaPods, run pod update.
  • If you're using Swift Package Manager, go to File > Workspace Actions > Resolve Package Dependencies.
  • Are you using any other 3rd party framework?
• Disable Bitcode:
  • Go to your project's target settings.
  • Under Build Settings, search for BITCODE and set Enable Bitcode to NO for both Debug and Release configurations.
  • Try building your project again.
  • If this works, means you project file is old, I would recommend to create a new project file and move all the files to the new project.
• Disable Arm64e Architecture:
  • Go to your project's target settings.
  • Under Build Settings, search for Valid Architectures.
  • Remove arm64e from the list for both Debug and Release configurations.
  • Try building your project again.
  • Again. If this works, means you project file is old, I would recommend to create a new project file and move all the files to the new project.
• Check for Third-Party Libraries:
  • If you're using any third-party libraries, check if they are compatible with the latest version of Xcode and iOS

However, my recommendation is to create a new project file:

• Create a New Project:
  • As a last resort, create a new empty project and gradually copy over your code and assets.
  • This can help you identify if the issue is specific to your project's setup or a general problem.

Remember to archive your project again after making each change to ensure that the issue is resolved in both debug and release modes.

Albert Pascual
  Worldwide Developer Relations.

Hello, I have the same problem. Did you finally solve it?

Hello, I have the same problem, have you solved it?

Thanks Albert for your answer.

Before posting this question I also clear cache/restart Mac mini, even update all to latest macOS and Xcode 16.2.

First, the project still can archive to IPA file so I don't think any issue with pod or 3rd.

Second, if I set Minimum iOS to 13, there is no issue so far. The issue happen only when set minimum to iOS 15.

Due to project still archivable to IPA so I think there is the config works in release mode but doesn't work in debug mode.

So after trying all of them, seem no option work for me. On internet they mention about linker flag but it doesn't work for me too.

Thanks for providing that, I am interested in knowing the mismatch that is causing the error.

Have you tried to create a new project in Xcode 16.2 and then move all your source code to see if that fixes the issue? Then compare the project files and let me know what Architectures you had in the old project that are missing on the new project.

Albert Pascual
  Worldwide Developer Relations.

Hello, I have the same problem, have you solved it?There's nothing we can do about it right now