diff --git a/app/views/settings/_issues.html.erb b/app/views/settings/_issues.html.erb
index dcf5df8..c723585 100644
--- a/app/views/settings/_issues.html.erb
+++ b/app/views/settings/_issues.html.erb
@@ -13,7 +13,7 @@
 
 <p><%= setting_select :issue_done_ratio, Issue::DONE_RATIO_OPTIONS.collect {|i| [l("setting_issue_done_ratio_#{i}"), i]} %></p>
 
-<p><%= setting_multiselect :non_working_week_days, (1..7).map {|d| [day_name(d), d]}, :inline => true %></p>
+<p><%= setting_multiselect :non_working_week_days, (1..7).map {|d| [day_name(d), d.to_s]}, :inline => true %></p>
 
 <p><%= setting_text_field :issues_export_limit, :size => 6 %></p>
 
diff --git a/config/settings.yml b/config/settings.yml
index 130e263..83c0d86 100644
--- a/config/settings.yml
+++ b/config/settings.yml
@@ -223,5 +223,5 @@ thumbnails_size:
 non_working_week_days:
   serialized: true
   default:
-  - 6
-  - 7
+  - '6'
+  - '7'