How to Change the Theme for Anonymous Users

 

SharePoint Foundation 2010 does not support displaying custom themes to anonymous users. To work around this, you can edit the v4 master page to add a link to the theme's CSS file.

Getting the link to the theme CSS

1. Log into your SharePoint site in a web browser.
2. View the Source code for the root page (in IE, right mouse click on the page and select View Source).
3. After the </title> tag, usually found on line 9, copy the CSS link line for later use.
   • Example: <link rel="stylesheet" type="text/css" href="/_themes/0/corev4-8A0ABD2F.css?ctag=1"/>

Applying the theme CSS file

1. Log into your SharePoint site using SharePoint Designer 2010
2. Under Site Objects, click on Master Pages
3. Click on v4.master
4. Click on Edit file
5. Before the closing heading tag </head> usually found on line 35, paste the CSS link line
   • Example: <link rel="stylesheet" type="text/css" href="/_themes/0/corev4-8A0ABD2F.css?ctag=1"/>
6. Save the changes to the v4 master page
7. The first time you edit and save the v4 master page, you will receive a Site Definition Page Warning.
   
8. Click Yes

Note:  This will need to be done for every subsite and if you change the theme.