diff --git a/railties/lib/rails/generators/rails/master_key/master_key_generator.rb b/railties/lib/rails/generators/rails/master_key/master_key_generator.rb
index 82968985dc..21664ea86d 100644
--- a/railties/lib/rails/generators/rails/master_key/master_key_generator.rb
+++ b/railties/lib/rails/generators/rails/master_key/master_key_generator.rb
@@ -27,7 +27,9 @@ module Rails
       end
 
       def add_master_key_file_silently(key = nil)
-        key_file_generator.add_key_file_silently(MASTER_KEY_PATH, key)
+        unless MASTER_KEY_PATH.exist?
+          key_file_generator.add_key_file_silently(MASTER_KEY_PATH, key)
+        end
       end
 
       def ignore_master_key_file
diff --git a/railties/test/generators/app_generator_test.rb b/railties/test/generators/app_generator_test.rb
index 23e6371a79..cc4a376d31 100644
--- a/railties/test/generators/app_generator_test.rb
+++ b/railties/test/generators/app_generator_test.rb
@@ -653,10 +653,11 @@ class AppGeneratorTest < Rails::Generators::TestCase
     assert_empty output
   end
 
-  def test_force_option
+  def test_force_option_overwrites_every_file_except_master_key
     run_generator [File.join(destination_root, "myapp")]
     output = run_generator [File.join(destination_root, "myapp"), "--force"]
     assert_match(/force/, output)
+    assert_no_match("force  config/master.key", output)
   end
 
   def test_application_name_with_spaces