Same here. I thought it will be easy to export an iOS version app on OS X but it causes lots of problems and OS X running on a laptop isn’t really fast at all. It took me a whole day to deal with this issue but still no luck.
and it turns out the newest version Xcode doesn’t work with old OS X… I need to install Xcode v7.
If nothing works out, I will use MacinCloud.com (www.macincloud.com)… however it’s ideal to have a solution on my windows 10 laptop.