Missing the Rails 2.3.5 gem. Please `gem install -v=2.3.5 rails` although Rails IS already installed

So it appears that Rails apps sometimes boot up strangely… I have a server properly configured that already runs about 5 rails applications, without any single issue ; but as I’m trying to install a copy of Fat Free CRM this morning, the server crashs and application boot fails with this weird message :>Missing the Rails 2.3.5 gem. Please gem install -v=2.3.5 rails, update your RAILSGEMVERSION setting in config/environment.rb for the Rails version you do have installed

I digged a little deeper into it and found that Rails startup is not very verbose nor curious at all : it simply throw out this message whatever could be the error !!! In order to raise the real and specific error that crash you boot, you’ll have to edit the /config/boot.rb file, and found these lines :

rescue Gem::LoadError => loaderror $stderr.puts %(Missing the Rails #{version} gem. Please gem install -v=#{version} rails, update your RAILSGEMVERSION setting in config/environment.rb for the Rails version you do have installed, or comment out RAILSGEMVERSION to use the latest version installed.) exit 1 end Now, add this at the beginning of the rescue block : raise loaderror.inspect . This should throw out the real and usable error message.