diff --git a/lib/redmine/info.rb b/lib/redmine/info.rb
index 60d682c77..1933a1cda 100644
--- a/lib/redmine/info.rb
+++ b/lib/redmine/info.rb
@@ -20,16 +20,13 @@ module Redmine
           ["Mailer delivery", ActionMailer::Base.delivery_method]
         ].map {|info| "  %-30s %s" % info}.join("\n") + "\n"
 
-        theme = Setting.ui_theme.blank? ? 'Default' : Setting.ui_theme.capitalize
-        unless Setting.ui_theme.blank?
-          theme_js  = (if Redmine::Themes.theme(Setting.ui_theme).javascripts.include?('theme')
-                         ' (includes JavaScript)'
-                       else
-                         ''
-                       end
-                      )
+        theme_string = ''
+        theme_string += (Setting.ui_theme.blank? ? 'Default' : Setting.ui_theme.capitalize)
+        unless Setting.ui_theme.blank? ||
+          Redmine::Themes.theme(Setting.ui_theme).nil? ||
+          !Redmine::Themes.theme(Setting.ui_theme).javascripts.include?('theme')
+          theme_string += ' (includes JavaScript)'
         end
-        theme_string = (theme + theme_js.to_s).to_s
 
         s << "Redmine settings:\n"
         s << [
diff --git a/test/unit/lib/redmine/info_test.rb b/test/unit/lib/redmine/info_test.rb
index 8b7016cd8..d83c60639 100644
--- a/test/unit/lib/redmine/info_test.rb
+++ b/test/unit/lib/redmine/info_test.rb
@@ -26,4 +26,11 @@ class Redmine::InfoTest < ActiveSupport::TestCase
     assert_kind_of String, env
     assert_match 'Redmine version', env
   end
+
+  def test_theme_with_invalid_theme_setting
+    Setting.ui_theme = 'foo'
+    env = Redmine::Info.environment
+
+    assert_match 'Redmine theme', env
+  end
 end