I have been having problems with unpacked gems throwing up warning messages about missing specification files. It looks something like this: config.gem: Unpacked gem cucumber-0.3.11 in vendor/gems has no specification file. Run 'rake gems:refresh_specs' to fix this. It has been my experience that running rake gems:refresh_specs doesn't fix the problem at all. What I have found to work though is to add a file named .specification into the root of the unpacked gem. In the case of cucumber, I added this file: --- !ruby/object:Gem::Specification name: cucumber version: !ruby/object:Gem::Version version: 0.3.11 require_paths: - lib platform: ruby Adjust the gem name and version for any other warnings you get and they should all go away.