If you get an error like this:
Unable to launch /home/bruce/Projects/myproject/tmp/capybara/capybara-201110311210111407691101.html
Rails LTS provides security patches for old versions of Ruby on Rails (2.3, 3.2, 4.2 and 5.2)
... update your launchy gem. It failed for us in version 0.4.x. We could fix the issue by upgrading to 2.0.5.
launchy