I just updated my mac to 10.12 Sierra and now my appium tests in the simulator are taking 20 minutes to run one line of code. The test eventually passes, so there are no errors. I went from appium 1.6.3 to 1.6.6-beta and there is no difference in speed.
Not having this issue but I think the best advice is to delete all the Simulators in Xcode and then recreate them. I’ve fixed similar issues by doing this in the past.
I’m not sure what you mean by delete and recreate. Do you mean by going into the preferences/components area? Can you please explain how you did this, thanks!