diff --git a/app/assets/javascripts/exercises.js.erb b/app/assets/javascripts/exercises.js.erb
index 95b5539e..08d119ad 100644
--- a/app/assets/javascripts/exercises.js.erb
+++ b/app/assets/javascripts/exercises.js.erb
@@ -236,7 +236,6 @@ $(document).on('turbolinks:load', function() {
         $('#exercise_unpublished').prop('checked', true);
       }
     })
-
   };
 
   var observeExportButtons = function(){
diff --git a/app/controllers/exercises_controller.rb b/app/controllers/exercises_controller.rb
index 6df096fe..48ac4dbd 100644
--- a/app/controllers/exercises_controller.rb
+++ b/app/controllers/exercises_controller.rb
@@ -141,7 +141,6 @@ class ExercisesController < ApplicationController
           exported: false
         }
       )
-
     }, status: 200
   end
 
diff --git a/app/models/code_ocean/file.rb b/app/models/code_ocean/file.rb
index 91ad6e54..a68b585b 100644
--- a/app/models/code_ocean/file.rb
+++ b/app/models/code_ocean/file.rb
@@ -7,7 +7,6 @@ module CodeOcean
     def validate(record)
       existing_files = File.where(name: record.name, path: record.path, file_type_id: record.file_type_id,
                                   context_id: record.context_id, context_type: record.context_type).to_a
-
       unless existing_files.empty?
         if (not record.context.is_a?(Exercise)) || (record.context.new_record?)
           record.errors[:base] << 'Duplicate'
diff --git a/app/services/proforma_service/import.rb b/app/services/proforma_service/import.rb
index 7ab31055..b8ec628b 100644
--- a/app/services/proforma_service/import.rb
+++ b/app/services/proforma_service/import.rb
@@ -55,8 +55,8 @@ module ProformaService
       end
 
       filenames.select { |f| f[/\.xml$/] }.any?
-    # rescue Zip::Error
-    # raise Proforma::InvalidZip
+    rescue Zip::Error
+      raise Proforma::InvalidZip
     end
   end
 end
diff --git a/app/views/exercises/_export_actions.html.slim b/app/views/exercises/_export_actions.html.slim
index 6b5a0554..0008670d 100644
--- a/app/views/exercises/_export_actions.html.slim
+++ b/app/views/exercises/_export_actions.html.slim
@@ -1,18 +1,18 @@
 - if error
     = button_tag type: 'button', class:'btn btn-primary pull-right export-button export-retry-button', data: {exercise_id: exercise.id} do
       i.fa.fa-refresh.confirm-icon
-      = ' Retry'
+      = t('exercises.export_codeharbor.buttons.retry')
 - else
   - unless exported
     - if update_right
       = button_tag type: 'button', class:'btn btn-primary pull-right export-action export-button', data: {exercise_id: exercise.id, export_type: 'export'} do
         i.fa.fa-check.confirm-icon
-        = ' Export'
+        = t('exercises.export_codeharbor.buttons.export')
     - else
       = button_tag type: 'button', class:'btn btn-primary pull-right export-action export-button', data: {exercise_id: exercise.id, export_type: 'create_new'} do
         i.fa.fa-check.confirm-icon
-        = ' Create new'
+        = t('exercises.export_codeharbor.buttons.create_new')
 
 = button_tag type: 'submit', class:'btn btn-secondary pull-right export-button', data: {dismiss: 'modal'} do
   i.fa.fa-remove.abort-icon
-  = exported ? ' Close' : ' Abort'
+  = exported ? t('exercises.export_codeharbor.buttons.close') : t('exercises.export_codeharbor.buttons.abort')
diff --git a/app/views/exercises/_export_dialogcontent.html.slim b/app/views/exercises/_export_dialogcontent.html.slim
index 92066666..bae04880 100644
--- a/app/views/exercises/_export_dialogcontent.html.slim
+++ b/app/views/exercises/_export_dialogcontent.html.slim
@@ -1,5 +1,3 @@
 #export-exercise
   .export-message
-    = 'This should not be seen'
   .export-exercise-actions
-    = 'This neither'
diff --git a/app/views/exercises/_form.html.slim b/app/views/exercises/_form.html.slim
index d9ad42f6..dcf31568 100644
--- a/app/views/exercises/_form.html.slim
+++ b/app/views/exercises/_form.html.slim
@@ -11,7 +11,7 @@
     = f.pagedown :description, input_html: { preview: true, rows: 10 }
   .form-group
     = f.label(:execution_environment_id)
-    = f.collection_select(:execution_environment_id, @execution_environments, :id, :name, {include_blank: 'None'}, class: 'form-control')
+    = f.collection_select(:execution_environment_id, @execution_environments, :id, :name, {include_blank: t('exercises.form.none')}, class: 'form-control')
   /.form-group
     = f.label(:instructions)
     = f.hidden_field(:instructions)
diff --git a/config/locales/en.yml b/config/locales/en.yml
index fb9f2e55..77d79d4f 100644
--- a/config/locales/en.yml
+++ b/config/locales/en.yml
@@ -331,6 +331,12 @@ en:
       export_failed: 'Export has failed.<br>ID: %{id}<br>Title: %{title}<br><br>Error: %{error}'
       error: 'An error occurred while contacting Codeharbor<br>Error: %{message}'
       checking_codeharbor: Checking whether exercise exists on Codeharbor.
+      buttons:
+        retry: ' Retry'
+        export: ' Export'
+        create_new: ' Create new'
+        close: ' Close'
+        abort: ' Abort'
     file_form:
       hints:
         feedback_message: This message is used as a hint for failing tests.
@@ -341,6 +347,7 @@ en:
       click_to_collapse: "Click to expand/collapse..."
       unpublish_warning: This will unpublish the exercise. Any student trying to implement it will get an error message, until it is published again.
       no_execution_environment_selected: Select an execution environment before publishing the exercise.
+      none: None
     implement:
       alert:
         text: 'Your browser does not support features required for using %{application_name}. Please access %{application_name} using a modern browser.'