I have a rails application that I deploy on Heroku. I'm using several different machines, and I noticed that when I add new dependencies (so that Gemfile.lock is rebuilt) and do bundle install on my Windows computer at home, push to Heroku fails with the following error: Unresolved dependencies detected; Installing... Windows Gemfile.lock detected, ignoring it. You have modified your Gemfile in development but did not check the resulting snapshot (Gemfile.lock) into version control ... Gemfile.lock IS under version control, but Heroku appearently chooses to ignore it since it's created in Windows, and then complains that it's missing seconds later. Why does this happen? And how can I solve it?