I am running Xcode 12.5.1 on Big Sur 11.6 I have been building apps with Xcode for more than four years. Lately I have one app that all too frequently throws the following error:

**Illegal Instruction: 4**

I am using Swift with UIKit and a combination of Storyboards, Xibs and programmatic code.

I have searched extensively for a solution and have seen this [stackoverflow post](https://stackoverflow.com/questions/14268887/what-is-the-illegal-instruction-4-error-and-why-does-mmacosx-version-min-10) more than once in my quest. The most popular response is dated and this problem only happens on one specific app. I have reinstalled Xcode, I have rebooted, re-cloned the repository and cleaned the build folder until it is spotless. Co-workers do not experience the issue with the same repository.

How can I troubleshoot the root cause of this annoying error?