TZInfo::DataSourceNotFound error starting Rails v4.1.0 server on Windows

I have created a new application using Ruby on Rails v4.1.0. When attempting to start a server or console on Windows, I am encountering the following error:

$ rails server
Booting WEBrick
Rails 4.1.0 application starting in development on ....

Exiting
c:/RailsInstaller/Ruby2.0.0/lib/ruby/gems/2.0.0/gems/tzinfo-1.1.0/lib/tzinfo/data_source.rb:199:
in `rescue in create_default_data_source': 
No timezone data source could be found. To resolve this, either install 
TZInfo::Data (e.g. by running `gem install tzinfo-data`) or specify a zoneinfo 
directory using `TZInfo::DataSource.set(:zoneinfo, zoneinfo_path)`.
(TZInfo::DataSourceNotFound) 
from c:/RailsInstaller/Ruby2.0.0/lib/ruby/gems/2.0.0/gems/tzinfo-1.1.0/lib/tzinfo/data_source.rb:196:
in `create_default_data_source'

How can I resolve this error?

Resolving the Error

To resolve this error, you'll need to make sure that the tzinfo-data gem is being included in your Gemfile.

First of all, check your Gemfile to see if there is an existing reference to tzinfo-data. If there isn't already a reference, then add the following line:

gem 'tzinfo-data'

You may find that there is already a line like the following:

gem 'tzinfo-data', platforms: [:mingw, :mswin]

If you are using a 64-bit version of Ruby on Windows, then add :x64_mingw to the list of platforms as follows:

gem 'tzinfo-data', platforms: [:mingw, :mswin, :x64_mingw]

Alternatively, you can remove the platforms option altogether.

After doing this, run bundle update at the command line to install the tzinfo-data gem and you'll then be able to start your Rails server or console.

Background

The TZInfo::DataSourceNotFound error is being raised by TZInfo, a dependency of the Active Support component of Rails. TZInfo is looking for a source of time zone data on your system, but failing to find one.

On many Unix-based systems (e.g. Linux), TZInfo is able to use the system zoneinfo directory as a source of data. However, Windows doesn't include such a directory, so the tzinfo-data gem needs to be installed instead. The tzinfo-data gem contains the same zoneinfo data, packaged as a set of Ruby modules.

Rails generates a default Gemfile when the application is first created. If the application is created on Windows, then a dependency for tzinfo-data will be included. However (as of Rails version 4.1.0), this omits :x64_mingw from the list of platforms, so doesn't work correctly on 64-bit Windows versions of Ruby. This should be fixed in future Rails releases.

I had to add two gems to get the server to start..

gem 'tzinfo-data'
gem 'tzinfo'

Then bundle install.

I had that error when trying to install Redmine in a Docker container:

RAILS_ENV=production bundle exec rake db:migrate

gave me the error because package tzdata was not installed in my Ubuntu image.

apt-get update && apt-get install tzdata -y

did the trick.