diff --git a/config/initializers/core_extensions.rb b/config/initializers/core_extensions.rb
index 861491ae..a8b484f4 100644
--- a/config/initializers/core_extensions.rb
+++ b/config/initializers/core_extensions.rb
@@ -123,6 +123,15 @@ module Jekyll
           spec.name == name
         end
 
+        unless spec
+          I18n.with_locale(locale) do
+            raise ArgumentError, I18n.t('activerecord.errors.models.site.attributes.design_id.missing_gem', theme: name)
+          rescue ArgumentError => e
+            ExceptionNotifier.notify_exception(e, data: { theme: name, site: site.path })
+            raise
+          end
+        end
+
         ruby_version = Gem::Version.new(RUBY_VERSION)
         ruby_version.canonical_segments[2] = 0
         base_path = Rails.root.join('_storage', 'gems', File.basename(site.source), 'ruby',
@@ -146,6 +155,11 @@ module Jekyll
     private
 
     def gemspec; end
+
+    # @return [Symbol]
+    def locale
+      @locale ||= (site.config['locale'] || site.config['lang'] || I18n.locale).to_sym
+    end
   end
 
   # No necesitamos los archivos de la plantilla
diff --git a/config/locales/en.yml b/config/locales/en.yml
index 186fdc41..b9c341f9 100644
--- a/config/locales/en.yml
+++ b/config/locales/en.yml
@@ -192,6 +192,7 @@ en:
             deploys:
               deploy_local_presence: 'We need to be build the site!'
             design_id:
+              missing_gem: "Site is configured to use %{theme} theme, but the corresponding gem is missing from Gemfile"
               layout_incompatible:
                 error: "Design can't be changed because there are posts with incompatible layouts"
                 help: "Your site has posts with layouts only compatible with the current design.  If you change it, the site won't work as you expect.  If you're trying out designs, you can delete posts in the following incompatible layouts:: %{layouts}."
diff --git a/config/locales/es.yml b/config/locales/es.yml
index d11ddd8a..a62e18ad 100644
--- a/config/locales/es.yml
+++ b/config/locales/es.yml
@@ -192,6 +192,7 @@ es:
             deploys:
               deploy_local_presence: '¡Necesitamos poder generar el sitio!'
             design_id:
+              missing_gem: "El sitio usa la plantilla %{theme} pero la gema correspondiente no se encuentra en el Gemfile"
               layout_incompatible:
                 error: 'No se puede cambiar la plantilla porque hay artículos con formatos incompatibles'
                 help: 'En tu sitio hay artículos que solo son compatibles con el diseño actual, si cambias la plantilla el sitio no funcionará como esperas.  Si estás probando plantillas, puedes eliminar los artículos en los formatos incompatibles: %{layouts}.'