diff --git a/config/routes.rb b/config/routes.rb
index e50e9c4b..aa8a4a5a 100644
--- a/config/routes.rb
+++ b/config/routes.rb
@@ -166,7 +166,7 @@ if Redmine::Plugin.installed? :redmine_dmsf
     end
 
     # WebDAV workaround for clients checking WebDAV availability in the root
-    if Redmine::Plugin.installed?(:easy_extensions)
+    unless Redmine::Plugin.installed?(:easy_extensions)
       match '/', to: lambda { |env| [405, {}, [env.to_s]] }, via: [:propfind, :options]
     end
     match '/dmsf', to: lambda { |env| [405, {}, [env.to_s]] }, via: [:propfind, :options]