Note: upon restart of your computer and launch of Xcode, you will be able to get/install the simulator

I had the same issue. This is what helped me (I gleaned this knowledge from another thread): delete the 'Developer" file in hard drive>Library>Developer Empty the trash. Deinstall Xcode. Re-install Xcode Restart your computer Open Xcode, the simulator should be able to be installed now The "Developer" folder automatically gets created upon installation/launch of Xcode. I hope this works! PS. If anyone knows how to fix the "Unknown file type" error in an Xcode build, please let me know!