I was having the “TimeoutError: Timed out waiting for connection to DTServiceHub after 15.0 seconds.” Often. Have searched online for a solution but could find. How ever, I have done the following and have solved. After that, I have a hypothesis why it happened: I use OneDrive. I turned it on and waited it to completely sync the files I had created a new single file, with the initial “Hello, world!”. Don’t change anything! The preview wont work yet. Run the application like it is ready. Wait the iPhone simulator initialize for complete, and the app shows the “Hello, world!”. Close the app on simulator Close the simulator Close the Xcode Restart the Mac It should work! In my case I was re-thinking what have I done since the last time the Xcode´s Preview was working. Turns out I have tried to run the app simulation on simulator and it was taking too long and I just closed the simulator without it has been completely on. My hypothesis is that, closing it down wrongly maybe had messed up with some Xcode configurations and when I turned on and off correctly this time it has been fixed. Now I can use my previews normally! Hope it helps!