I’ve had some trouble installing gems on windows instances using bundle install. I had this problem first at ~2009. The problem is missing certificates. While this fix is correct, a quick and dirty approach is to make sure that your gem files have source http instead of https: # A sample Gemfile source "http://rubygems.org" gem 'albacore' gem 'nuget_helper' This means that the communication to download gems from rubygems is not private.