Ignoring bcrypt-3.1.11 because its extensions are not built. Try: gem pristine bcrypt --version 3.1.11
<p><strong>In MacOS Sierra [22 Sept 2016]</strong></p>

<p>after upgrade ruby to 5.3.1 via <strong>rvm</strong> and then checked <strong>ruby -v</strong></p>

<pre><code>ruby 2.3.1p112 (2016-04-26 revision 54768) [x86_64-darwin16]
</code></pre>

<p>Then I tried to install rails by using gem</p>

<pre><code>gem install rails -v 5.0.0.1
</code></pre>

<p>it shows errors </p>

<pre><code>  Ignoring bcrypt-3.1.11 because its extensions are not built.  Try: gem pristine bcrypt --version 3.1.11
Ignoring binding_of_caller-0.7.2 because its extensions are not built.  Try: gem pristine binding_of_caller --version 0.7.2
Ignoring byebug-9.0.5 because its extensions are not built.  Try: gem pristine byebug --version 9.0.5
Ignoring byebug-8.2.2 because its extensions are not built.  Try: gem pristine byebug --version 8.2.2
Ignoring capybara-webkit-1.11.1 because its extensions are not built.  Try: gem pristine capybara-webkit --version 1.11.1
Ignoring debug_inspector-0.0.2 because its extensions are not built.  Try: gem pristine debug_inspector --version 0.0.2
/Users/chutipongroobklom/.rvm/rubies/ruby-2.3.1/lib/ruby/2.3.0/rubygems/core_ext/kernel_require.rb:55:in `require': incompatible library version - /Users/chutipongroobklom/.rvm/gems/ruby-2.3.1/gems/io-console-0.4.6/lib/io/console.bundle (fatal)
    from /Users/chutipongroobklom/.rvm/rubies/ruby-2.3.1/lib/ruby/2.3.0/rubygems/core_ext/kernel_require.rb:55:in `require'
    from /Users/chutipongroobklom/.rvm/rubies/ruby-2.3.1/lib/ruby/2.3.0/rubygems/user_interaction.rb:9:in `&lt;top (required)&gt;'
    from /Users/chutipongroobklom/.rvm/rubies/ruby-2.3.1/lib/ruby/2.3.0/rubygems/core_ext/kernel_require.rb:55:in `require'
    from /Users/chutipongroobklom/.rvm/rubies/ruby-2.3.1/lib/ruby/2.3.0/rubygems/core_ext/kernel_require.rb:55:in `require'
    from /Users/chutipongroobklom/.rvm/rubies/ruby-2.3.1/lib/ruby/2.3.0/rubygems/command.rb:10:in `&lt;top (required)&gt;'
    from /Users/chutipongroobklom/.rvm/rubies/ruby-2.3.1/lib/ruby/2.3.0/rubygems/core_ext/kernel_require.rb:55:in `require'
    from /Users/chutipongroobklom/.rvm/rubies/ruby-2.3.1/lib/ruby/2.3.0/rubygems/core_ext/kernel_require.rb:55:in `require'
    from /Users/chutipongroobklom/.rvm/rubies/ruby-2.3.1/lib/ruby/2.3.0/rubygems/command_manager.rb:8:in `&lt;top (required)&gt;'
    from /Users/chutipongroobklom/.rvm/rubies/ruby-2.3.1/lib/ruby/2.3.0/rubygems/core_ext/kernel_require.rb:55:in `require'
    from /Users/chutipongroobklom/.rvm/rubies/ruby-2.3.1/lib/ruby/2.3.0/rubygems/core_ext/kernel_require.rb:55:in `require'
    from /Users/chutipongroobklom/.rvm/rubies/ruby-2.3.1/lib/ruby/2.3.0/rubygems/gem_runner.rb:9:in `&lt;top (required)&gt;'
    from /Users/chutipongroobklom/.rvm/rubies/ruby-2.3.1/lib/ruby/2.3.0/rubygems/core_ext/kernel_require.rb:55:in `require'
    from /Users/chutipongroobklom/.rvm/rubies/ruby-2.3.1/lib/ruby/2.3.0/rubygems/core_ext/kernel_require.rb:55:in `require'
    from /Users/chutipongroobklom/.rvm/rubies/ruby-2.3.1/bin/gem:9:in `&lt;main&gt;'
</code></pre>

<ol>
<li>What's going on ?</li>
<li>What is the root cause ?</li>
<li>What should I do next ?</li>
<li>How can I prevent this error in the future ?</li>
</ol>

<p>Thank you in advance</p>