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

Question

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?

Accepted Answer

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.

Note that there is a bug in Bundler that means there's currently no platform option that will match 64-bit Ruby 3.1 on Windows. The solution here to remove the `platforms` option.

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 Rails (up to version 4.1.x) omitted `:x64_mingw` from the list of platforms and therefore didn't work correctly on 64-bit Windows versions of Ruby.

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

Solution

Problem