Cannot load such file -- bcrypt_ext - ruby-on-rails

Question

I'm currently experiencing the failure of bcrypt's encryptor while using Devise for Rails 5.0.1. I never had this issue before with the earlier Rails 4.2. I can't register new users through Devise. I will post information with regards to my gemfile and server log.
Gemfile.rb
gem 'bcrypt', platforms: :ruby
# Devise
gem 'devise'
gem 'devise_security_extension'
gem 'redis'
# Bundle edge Rails instead: gem 'rails', github: 'rails/rails'
gem 'rails', '~> 5.0.1'
Server log
Started POST "/register" for 127.0.0.1 at 2017-01-12 13:50:05 -0500
Processing by Users::RegistrationsController#create as HTML
Parameters: {"utf8"=>"✓", "authenticity_token"=>"bH6n7iWLhPMECDzTVkMyTc9FXtvkGrq5+K4wFs1g8Bxbjq9ShaLJP5gn72SFQlHc01j2ao5JKcv57ClWAzwsmw==", "user"=>{"email"=>"craigcarl#codex.com", "username"=>"codex", "password"=>"[FILTERED]", "password_confirmation"=>"[FILTERED]"}, "commit"=>"Sign up"}
Completed 500 Internal Server Error in 258ms (ActiveRecord: 0.0ms)
LoadError - cannot load such file -- bcrypt_ext:
activesupport (5.0.1) lib/active_support/dependencies.rb:293:in `require'
activesupport (5.0.1) lib/active_support/dependencies.rb:293:in `block in require'
activesupport (5.0.1) lib/active_support/dependencies.rb:259:in `load_dependency'
activesupport (5.0.1) lib/active_support/dependencies.rb:293:in `require'
bcrypt-3.1.11-x86 (mingw32) lib/bcrypt.rb:16:in `rescue in <top (required)>'
bcrypt-3.1.11-x86 (mingw32) lib/bcrypt.rb:12:in `<top (required)>'
activesupport (5.0.1) lib/active_support/dependencies.rb:293:in `require'
activesupport (5.0.1) lib/active_support/dependencies.rb:293:in `block in require'
activesupport (5.0.1) lib/active_support/dependencies.rb:259:in `load_dependency'
activesupport (5.0.1) lib/active_support/dependencies.rb:293:in `require'
devise (4.2.0) lib/devise/encryptor.rb:1:in `<top (required)>'
activesupport (5.0.1) lib/active_support/dependencies.rb:293:in `require'
activesupport (5.0.1) lib/active_support/dependencies.rb:293:in `block in require'
activesupport (5.0.1) lib/active_support/dependencies.rb:259:in `load_dependency'
activesupport (5.0.1) lib/active_support/dependencies.rb:293:in `require'
devise (4.2.0) lib/devise/models/database_authenticatable.rb:147:in `password_digest'
devise (4.2.0) lib/devise/models/database_authenticatable.rb:40:in `password='
activemodel (5.0.1) lib/active_model/attribute_assignment.rb:46:in `public_send'
activemodel (5.0.1) lib/active_model/attribute_assignment.rb:46:in `_assign_attribute'
activemodel (5.0.1) lib/active_model/attribute_assignment.rb:40:in `block in _assign_attributes'
activemodel (5.0.1) lib/active_model/attribute_assignment.rb:39:in `each'
activemodel (5.0.1) lib/active_model/attribute_assignment.rb:39:in `_assign_attributes'
activerecord (5.0.1) lib/active_record/attribute_assignment.rb:26:in `_assign_attributes'
activemodel (5.0.1) lib/active_model/attribute_assignment.rb:33:in `assign_attributes'
activerecord (5.0.1) lib/active_record/core.rb:319:in `initialize'
activerecord (5.0.1) lib/active_record/inheritance.rb:65:in `new'
activerecord (5.0.1) lib/active_record/inheritance.rb:65:in `new'
devise (4.2.0) lib/devise/models/registerable.rb:20:in `new_with_session'
devise (4.2.0) app/controllers/devise/registrations_controller.rb:100:in `build_resource'
devise (4.2.0) app/controllers/devise/registrations_controller.rb:15:in `create'
actionpack (5.0.1) lib/action_controller/metal/basic_implicit_render.rb:4:in `send_action'
actionpack (5.0.1) lib/abstract_controller/base.rb:188:in `process_action'
actionpack (5.0.1) lib/action_controller/metal/rendering.rb:30:in `process_action'
actionpack (5.0.1) lib/abstract_controller/callbacks.rb:20:in `block in process_action'
activesupport (5.0.1) lib/active_support/callbacks.rb:126:in `call'
activesupport (5.0.1) lib/active_support/callbacks.rb:506:in `block (2 levels) in compile'
activesupport (5.0.1) lib/active_support/callbacks.rb:455:in `call'
activesupport (5.0.1) lib/active_support/callbacks.rb:101:in `__run_callbacks__'
activesupport (5.0.1) lib/active_support/callbacks.rb:750:in `_run_process_action_callbacks'
activesupport (5.0.1) lib/active_support/callbacks.rb:90:in `run_callbacks'
actionpack (5.0.1) lib/abstract_controller/callbacks.rb:19:in `process_action'
actionpack (5.0.1) lib/action_controller/metal/rescue.rb:20:in `process_action'
actionpack (5.0.1) lib/action_controller/metal/instrumentation.rb:32:in `block in process_action'
activesupport (5.0.1) lib/active_support/notifications.rb:164:in `block in instrument'
activesupport (5.0.1) lib/active_support/notifications/instrumenter.rb:21:in `instrument'
activesupport (5.0.1) lib/active_support/notifications.rb:164:in `instrument'
actionpack (5.0.1) lib/action_controller/metal/instrumentation.rb:30:in `process_action'
actionpack (5.0.1) lib/action_controller/metal/params_wrapper.rb:248:in `process_action'
activerecord (5.0.1) lib/active_record/railties/controller_runtime.rb:18:in `process_action'
actionpack (5.0.1) lib/abstract_controller/base.rb:126:in `process'
actionview (5.0.1) lib/action_view/rendering.rb:30:in `process'
actionpack (5.0.1) lib/action_controller/metal.rb:190:in `dispatch'
actionpack (5.0.1) lib/action_controller/metal.rb:262:in `dispatch'
actionpack (5.0.1) lib/action_dispatch/routing/route_set.rb:50:in `dispatch'
actionpack (5.0.1) lib/action_dispatch/routing/route_set.rb:32:in `serve'
actionpack (5.0.1) lib/action_dispatch/routing/mapper.rb:16:in `block in <class:Constraints>'
actionpack (5.0.1) lib/action_dispatch/routing/mapper.rb:46:in `serve'
actionpack (5.0.1) lib/action_dispatch/journey/router.rb:39:in `block in serve'
actionpack (5.0.1) lib/action_dispatch/journey/router.rb:26:in `each'
actionpack (5.0.1) lib/action_dispatch/journey/router.rb:26:in `serve'
actionpack (5.0.1) lib/action_dispatch/routing/route_set.rb:725:in `call'
rack (2.0.1) lib/rack/deflater.rb:35:in `call'
warden (1.2.6) lib/warden/manager.rb:35:in `block in call'
warden (1.2.6) lib/warden/manager.rb:34:in `catch'
warden (1.2.6) lib/warden/manager.rb:34:in `call'
rack (2.0.1) lib/rack/etag.rb:25:in `call'
rack (2.0.1) lib/rack/conditional_get.rb:38:in `call'
rack (2.0.1) lib/rack/head.rb:12:in `call'
rack (2.0.1) lib/rack/session/abstract/id.rb:222:in `context'
rack (2.0.1) lib/rack/session/abstract/id.rb:216:in `call'
actionpack (5.0.1) lib/action_dispatch/middleware/cookies.rb:613:in `call'
activerecord (5.0.1) lib/active_record/migration.rb:553:in `call'
actionpack (5.0.1) lib/action_dispatch/middleware/callbacks.rb:38:in `block in call'
activesupport (5.0.1) lib/active_support/callbacks.rb:97:in `__run_callbacks__'
activesupport (5.0.1) lib/active_support/callbacks.rb:750:in `_run_call_callbacks'
activesupport (5.0.1) lib/active_support/callbacks.rb:90:in `run_callbacks'
actionpack (5.0.1) lib/action_dispatch/middleware/callbacks.rb:36:in `call'
actionpack (5.0.1) lib/action_dispatch/middleware/executor.rb:12:in `call'
actionpack (5.0.1) lib/action_dispatch/middleware/remote_ip.rb:79:in `call'
better_errors (2.1.1) lib/better_errors/middleware.rb:84:in `protected_app_call'
better_errors (2.1.1) lib/better_errors/middleware.rb:79:in `better_errors_call'
better_errors (2.1.1) lib/better_errors/middleware.rb:57:in `call'
actionpack (5.0.1) lib/action_dispatch/middleware/debug_exceptions.rb:49:in `call'
web-console (3.4.0) lib/web_console/middleware.rb:135:in `call_app'
web-console (3.4.0) lib/web_console/middleware.rb:28:in `block in call'
web-console (3.4.0) lib/web_console/middleware.rb:18:in `catch'
web-console (3.4.0) lib/web_console/middleware.rb:18:in `call'
actionpack (5.0.1) lib/action_dispatch/middleware/show_exceptions.rb:31:in `call'
railties (5.0.1) lib/rails/rack/logger.rb:36:in `call_app'
railties (5.0.1) lib/rails/rack/logger.rb:24:in `block in call'
activesupport (5.0.1) lib/active_support/tagged_logging.rb:69:in `block in tagged'
activesupport (5.0.1) lib/active_support/tagged_logging.rb:26:in `tagged'
activesupport (5.0.1) lib/active_support/tagged_logging.rb:69:in `tagged'
railties (5.0.1) lib/rails/rack/logger.rb:24:in `call'
sprockets-rails (3.2.0) lib/sprockets/rails/quiet_assets.rb:13:in `call'
actionpack (5.0.1) lib/action_dispatch/middleware/request_id.rb:24:in `call'
rack (2.0.1) lib/rack/method_override.rb:22:in `call'
rack (2.0.1) lib/rack/runtime.rb:22:in `call'
activesupport (5.0.1) lib/active_support/cache/strategy/local_cache_middleware.rb:28:in `call'
actionpack (5.0.1) lib/action_dispatch/middleware/executor.rb:12:in `call'
actionpack (5.0.1) lib/action_dispatch/middleware/static.rb:136:in `call'
rack (2.0.1) lib/rack/sendfile.rb:111:in `call'
railties (5.0.1) lib/rails/engine.rb:522:in `call'
puma (3.6.2) lib/puma/configuration.rb:225:in `call'
puma (3.6.2) lib/puma/server.rb:578:in `handle_request'
puma (3.6.2) lib/puma/server.rb:415:in `process_client'
puma (3.6.2) lib/puma/server.rb:275:in `block in run'
puma (3.6.2) lib/puma/thread_pool.rb:116:in `block in spawn_thread'
Started POST "/__better_errors/4e4442c3f810d7b9/variables" for 127.0.0.1 at 2017-01-12 13:50:06 -0500

Answer 1

I had a similar problem today with ruby 2.3.3 and rails 4.2.4.
The problem was that bundle install of devise installed as a dependency another version of bcrypt (bcrypt (3.1.11 x86-mingw32) instead of bcrypt (3.1.11)) which was causing trouble with ruby 2.3 (it should work with all previous versions of ruby)
The solution I used is to install bcrypt outside of the gemfile, run bundle and then remove the second version of bcrypt :
$ gem list bcrypt
bcrypt (3.1.11 x86-mingw32)
$ gem uninstall devise && gem uninstall bcrypt
Successfully uninstalled devise-4.2.0
Successfully uninstalled bcrypt-3.1.11-x86-mingw32
$ gem install bcrypt --platform=Ruby
Temporarily enhancing PATH to include DevKit...
Building native extensions. This could take a while...
Successfully installed bcrypt-3.1.11
Parsing documentation for bcrypt-3.1.11
Installing ri documentation for bcrypt-3.1.11
Done installing documentation for bcrypt after 1 seconds
1 gem installed
$ gem list bcrypt
bcrypt (3.1.11)
$ bundle install
...
Installing bcrypt 3.1.11 (x86-mingw32)
...
Installing devise 4.2.0
Bundle complete! 25 Gemfile dependencies, 75 gems now installed.
$ gem list bcrypt
bcrypt (3.1.11 ruby x86-mingw32)
$ gem uninstall bcrypt
Select gem to uninstall:
1. bcrypt-3.1.11
2. bcrypt-3.1.11-x86-mingw32
3. All versions
> 2
Successfully uninstalled bcrypt-3.1.11-x86-mingw32
$ gem list bcrypt
bcrypt (3.1.11)
Hope that helps if you haven't solved your problem yet.

Answer 2

I also encountered the same problem, then I found some references and it's about version only.
When I changed bcrypt back to
bcrypt 3.1.0-x86-mingw32
from
bcrypt 3.1.11-x86-mingw32(the latest now)
Then make sure again in gemfile
gem 'bcrypt-ruby', '3.1.0', :require => 'bcrypt'
then it works fine.

Answer 3

I also face this same issue for ruby '2.3.3' and rails '5.2.0' but the only solution right now is to run:
gem uninstall bcrypt
gem install bcrypt --platform=ruby
temporary fix.

Answer 4

Maybe it's just the native binary is wrongly built or corrupted. Try below
Open a command console
cd to the gem directory C:\RailsInstaller\Ruby2.2.0\lib\ruby\gems\2.2.0\gems\bcrypt-3.1.10-x86-mingw32\ext\mri
Run ruby extconf.rb. It should create the Makefile
Run make. It will builde the extension libraries.
Run make install
See more at Fix issue "cannot load such file -- bcrypt_ext (LoadError)"

Answer 5

These steps to fix issue in MS Win 10 and 8
Uninstall all bcrypt
gem uninstall bcrypt
Go on lib/ruby/gems/2.3.0/gems/bcrypt-3.1.11-x86-mingw32/lib/ and copy bcrypt_ext.so file. and paste on desktop for now.
Uninstall all bcrypt again
gem uninstall bcrypt
Add in your project's gemfile
gem 'bcrypt', '~> 3.1.7'
Run commands
bundle install
bundle update
Paste copied bcrypt_ext.so in folder lib/ruby/gems/2.3.0/gems/bcrypt-3.1.11-x86-mingw32/lib/ from desktop.
Restart server
rails server
It works on win 7 and 10!!!