I am running Xcode 11.3.1 on macOS 10.14. (I know, I'm a little behind, but the Mail bug in Catalina still makes me wary.) Lately editing in Xcode has slowed to a crawl. Activity Monitor shows the process com.apple.dt.SKAgent running consistently at over 170%. Keystrokes are often delayed by up to several seconds, and I had to turn off "suggest completions while typing" altogether, which further slows me down. I've tried: rebooting closing any other open projects quitting Xcode and deleting the "DerivedData" directory The problem remains. Is there anything else I can try short of upgrading the OS? If the index parser is getting hung up on something, is there a way I can try to see what it might be?