Swift simulator won't launch in Xcode, despite successful build

Question

So I have a copy of Xcode 7.3 on my Mac and have been using it recently to develop in Swift. When I would run my code in the past, I noticed the app simulator would take a long time to boot up, and would often be unresponsive or have several errors for a period of time before starting to work as necessary in running my app.

Today, however, I went to run my code again, and the simulator fails to launch or run altogether. When I ran my code it said "build successful" but it has been almost 10 minutes and the simulator has not yet even popped up. Furthermore when I go to press the "stop" button to halt the application it doesn't seem to register this either.

Does anyone know what is wrong? I've been searching for the answer on here and Google for hours and have yet to find a way to fix this. Should I perhaps download the beta version of Xcode 8?

Answer 1

Just to clarify no Xcode will not delete your projects if you uninstall and reinstall it.

Answer 2

I agree with @Preston: don't upgrade to Beta if the latest stable version is giving you issues. It might be good to uninstall and then reinstall your current version. Perhaps that might work. Follow this guide for help uninstalling (contains info for recent versions): http://osxdaily.com/2012/02/20/uninstall-xcode/

This may seem like an obvious question but have you renamed any of your project files recently? When you go to Product > Scheme > Edit Scheme, under Run, is the correct "Your-Project.app" selected for Executable? Make sure you do a quick Clean "shift-command-k" after changing file names or schemes.

Also, try Simulator > Reset Content and Settings. Some people report that as helping fix freezing/non-responsive problems.

Answer 3

I wouldn't download the Xcode 8 if you are having problems in Xcode 7. Normally the beta versions cause more problems. The simulator takes up a lot of memory and if you're machine has less than 8 gb of RAM it could be the reason it is running so slow.