I too have been having this issue on Mac High Sierra.
A work around for this issue is to create your site as usual. And then when it crashes / hangs, create another ‘dummy’ site. Call this whatever you want and enter some temp password etc… When you hit create this will force Local to finish your first site, and now this new dummy site will hang / crash. You can then delete the dummy site.
A weird work around but it works for me.