SharePoint V3: Master Page Not Inherited By Non-Publishing Sites

Description

We encountered an issue where we had deployed a custom master page but not all of the sites in the site collection were recognizing the changes.

First, a little background on what we had done:
We opened the home page (a publishing site) of a SharePoint V3 site collection in SharePoint Designer. Next we copied the default.master and renamed the copy to custom.master. In custom.master we changed the logo in the header of the page to a custom image. Next, we opened the site collection in Internet Explorer and in Site Settings > Look and Feel > Master Page changed the Site Master page to custom.master. We clicked OK to save changes and reviewed the top level site. The header logo was updated. Next we reviewed another top level site, but these sites did not have the new header logo.

Solution

Site Settings > Look and Feel > Master PageSite Master Page:
* Select Specify a master page to be used by this site and all sites that inherit from it.
* Select custom.master from the drop down selection.
* Check off Reset all subsites to inherit this Site Master Page Setting

Site Settings > Look and Feel > System Master PageSite Master Page:
* Select Specify a master page to be used by this site and all sites that inherit from it.
* Select custom.master from the drop down selection.
* Check off Reset all subsites to inherit this Site Master Page Setting

The way this works is that the "Master Page" setting is used by publishing sites. The "System Master Page" is used by non-publishing sites. The terminology used in SharePoint V3 and SharePoint Designer are not intuitive, although the descriptions on the Site Settings > Look and Feel > Master Page do help a bit.

Thanks Marc Anderson for taking the time to read the small print and explain this out loud.

For further explanation, refer to Kathy's blog post, SharePoint Designer Snippets: Working with Master Pages, which helps clarify any confusion regarding this topic.

To expand on this blog post, I think of the Site Settings > Look and Feel > Master Page like this:

* Master Page = Custom Master Page = Publishing Sites
* System Master Page = Default Master Page = Non-Publishing Sites