Mingle help is located on the ThoughtWorks Studios website. The Mingle help files are also packaged with your local Mingle instance. In cases where network access is limited, you may want Mingle to link to your local help rather than the online help. 

1. Stop MingleServer

2. Open [Mingle_Installation_Directory]/config/initializers/document.rb

3. Change HELP_DOC_DOMAIN from

HELP_DOC_DOMAIN = ONLINE_HELP_DOC_DOMAIN

to

HELP_DOC_DOMAIN = " "

Please note: 

• Online help has a search feature (added in Mingle 3.2); local help cannot be searched.
• Online help may be more up to date than local help. As we make updates to help, we are able to post the latest help online.

The same has described in the help notes: http://www.thoughtworks-studios.com/mingle/3.3/help/advanced_mingle...