How to change the sub-site master page URL while creating it (sub-site) ? By default, it uses "default.master" is on its "master page gallery" list, want to change the master page url in such a way that it is pointing to its parent site-collections master page's url.
If you have created your own publishing site definition, you can also do this in your ONET.xml, as part of the properties of the OOB publishing feature. See the ChromeMasterUrl property below.
<WebFeatures> <Feature ID="22A9EF51-737B-4ff2-9346-694633FE4416"> <!-- Publishing --> <Properties xmlns="http://schemas.microsoft.com/sharepoint/"> <Property Key="ChromeMasterUrl" Value="~SiteCollection/_catalogs/masterpage/MYCUSTOMMASTER.master"/> <Property Key="WelcomePageUrl" Value="$Resources:cmscore,List_Pages_UrlName;/default.aspx"/> <Property Key="PagesListUrl" Value=""/> <Property Key="AvailableWebTemplates" Value="*-MYCUSTOMPUBLISHING#1"/> <Property Key="AvailablePageLayouts" Value=""/> <Property Key="AlternateCssUrl" Value="" /> <Property Key="SimplePublishing" Value="true" /> </Properties> </Feature> </WebFeatures>
Note this will only apply to publishing sites
In the browser, navigate to the root of your site collection (is probably a default.aspx page). Go to Site Actions > Site Settings > Modify All Site Settings. Under the Look and Feel column click "Master page". Set the Site Master Page to the master page you want to use. Your master page must be in the /_catalogs/masterpage directory at the root of the site collection. If you want to force all sub sites to use this master page for site pages, click the "Reset all subsites to inherit this Site Master Page setting" check box. Doing so will override any master page settings for subsites.
If it's still not working...Depending on what kind of site you're working with, there may be a master page directive in the page layout or page. Open the page layout or page in SharePoint Designer and remove the MasterPageFile declaration at the top (not the whole line, just the MasterPageFile="...").