I just downloaded xcode 9 beta, but there is no simulator within it. Try to add new simulator but the create button doesn't work. Please help
By "no simulator within it" I mean there is option to build with simulator.
See
.
Also, the create button doesn't work 
Go to Xcode Preferences -> Locations and go to the Derived Data location in Finder:
Just remove all contents from it, then right click on Xcode icon and quit it, and reopen it:
It is a simulator but you need to close Xcode 8 if you have it open and restart Xcode 9 beta.
This may happen due to multiple Xcode installed on machine or might be the deployment target is higher than the simulator OS version.
In order to resolve this navigate to following location : Xcode > Preference > location > comindline Tool > change the xcode version
and decrease the deployment target.
You may have removed iOS Simulators when you cleaned up disk space. I think I may have used DaisyDisk to remove files when I ran out of space.
You can re-add simulators using the Devices & Simulators window. (Shift + Command + 2)
Delete the derived data, close all your running Xcodes and restart your computer. It just helped me.
Apart from the simulators not showing, my project's storyboard was messed up also after upgrading to XCode 9. I simply restarted XCode and voila! Did not have to delete derived files - though it would probably not hurt.
You can do the same that @badhan-ganesh suggests (cleaning derived data) using the Xcode keyboard shortcut to clean derived data:
shift+alt+cmd+k
If needed, you can clean the project using Xcode keyboard shortcut:
shift+cmd+k
After that, restart Xcode and simulators should be available again.
Having a higher deployment target than what is installed on your simualtors also causes this.
Ensure your Deployment Target version in Build Settings is also set to the desired version (and that you have that version of the respective simulator installed). Suppose, if that were set to 10.3 and I didn’t have an iOS 10.3 simulator installed, I wouldn’t be able to see any simulators. But because it’s set to 10.1, and I have 10.1 simulators installed, I can see them.
When my xcode updated to 9.4 I face the same problem at first time. After force quit and start again solve the problem for me.
If you upgraded Xcode then follow the steps
1) Delete derived data,
Xcode-> Preferences -> Locations and select arrow symbol just before Advance button -> select all files and delete.
2) Quite Xcode
3) Quite Xcode from Dock
4) Open Xcode again.
:-) Hope this will help you.
I have Xcode 8.3 and Xcode 9.1, I came to this post to find a solution to missing simulators after forced upgrade to 9.1...
I was about to do the suggestion to remove the entire DerivedData directory, lucky closing Xcode 9.1 and restarting it worked. Moreover, I had to close all simulator(s).
I had to rebuild app apps on simulator again.
来源：https://stackoverflow.com/questions/44473923/xcode-9-doesnt-have-any-simulator-device