In my current work environment we use Babel for .NET to obfuscate our Xamarin binaries. The nice thing about Babel is that it’s the only Xamarin obfuscator that runs directly in macOS, eliminating the need for a Windows machine just for release builds. Things were working fine until after I installed the latest Visual Studio for Mac update along with the latest version of Xcode, Xamarin SDK, and .NET SDK. Turns out that Babel got removed from Mono’s Global Assembly Cache which is basically where DLLs (like Babel’s build DLL) get tracked so you don’t need to use an absolute path to the DLL to reference it. Adding the DLL back via gacutil solved it (if you have Babel the gacutil command syntax was included with the zip they send you). I am guessing you’ll need to do this every time there is a major update to the .NET SDK or Mono framework. Thanks to Alberto from Babel for the solution.