Favicon icon in SharePoint 2010
Copy the download image to your layouts folder
C:\Program Files\Common Files\Microsoft Shared\Web Server Extensions\14\TEMPLATE\IMAGES\CompanyName
Find the below in your master page and replace the new icon url.
<SharePoint:SPShortcutIcon runat="server" IconUrl="/_layouts/images/CompanyName/favicon.ico"/>
C:\Program Files\Common Files\Microsoft Shared\Web Server Extensions\14\TEMPLATE\IMAGES\CompanyName
Find the below in your master page and replace the new icon url.
<SharePoint:SPShortcutIcon runat="server" IconUrl="/_layouts/images/CompanyName/favicon.ico"/>
Comments
http://sureshpydi.blogspot.in/2013/06/change-favicon-image-in-sharepoint-2013.htmlorn sometimes