Thank you @amervil ! DispatchQueue.global().async { } That is what did it for me! For context: I was trying to run a simple apple script with NSAppleScript(..).executeAndReturnError(). The script was working just fine, but I was also receiving several of those "This method should not be called on the main thread.." errors in the console.

I'm experiencing the same issue... I have a custom file type that I'm trying to share, and the copy option never appears. Is this still not fixed?