Rails installation can't find active_model

Question

I created a fresh project using rails new Project -d=postgresql. If I then run rails server, I get the following error message:

C:/GemRepository/gems/actionpack-3.1.3/lib/action_dispatch.rb:34:in `require': cannot load such file -- active_model (LoadError)
    from C:/GemRepository/gems/actionpack-3.1.3/lib/action_dispatch.rb:34:in `<top (required)>'
    from C:/GemRepository/gems/railties-3.1.3/lib/rails/commands/server.rb:3:in `require'
    from C:/GemRepository/gems/railties-3.1.3/lib/rails/commands/server.rb:3:in `<top (required)>'
    from C:/GemRepository/gems/railties-3.1.3/lib/rails/commands.rb:48:in `require'
    from C:/GemRepository/gems/railties-3.1.3/lib/rails/commands.rb:48:in `<top (required)>'
    from script/rails:6:in `require'
    from script/rails:6:in `<main>'

I also tried

gem which active_model

which returned

C:/GemRepository/gems/activemodel-3.1.1/lib/active_model.rb

Please help me.

Answer 1

I had a similar error and it was due to accidentally corrupting my Gemfile, so it is worth checking that. If it is version controlled then just git checkout Gemfile and bundle update to rebuild.

Answer 2

gem uninstall active-model and perfomr gem install active-model

Answer 3

Had this problem, came across this post. This fixed it for me:

rvm gemset pristine

Answer 4

Well, I managed to solve it.

I restarted my computer, deleted everything from my gem repository, reinstalled rubygems (ruby setup.rb) and reinstalled rails (gem install rails).

Thanks anyway :)

Answer 5

Run the bundle command from the project directory

Answer 6

What version of rails is in the gem file? And have you run 'bundle install'?

I notice that Actionpack is 3.1.3 is called by the server, but the activemodel found is 3.1.1.