Are you seeing a duplicate site title and tagline in your WordPress site? Have you recently installed Yoast WordPress SEO Plugin? If yes, that is why!
You have defined a site title and a tagline on your general settings. Yoast plugin has a “Titles & Metas” section where it uses the “site title” and “tagline” values in your general settings to generate its own site title and tagline values. The problem is it does not overwrite/replace the ones you typed in the general settings section of your WordPress installation but creates its own values and appends that. I believe this is a problem to be fixed with the plugin. I would like to see a setting to enable/disable titles created by Yoast and I would expect to have a single site title and tagline on my site once I enable Yoast.
Anyways. Here is how you can solve this problem without coding.
1- Go to the General Settings of WordPress
2- Remove Site Title and Tagline (Note the values somewhere if you like since we’ll be using them on SEO settings)
3- Now go to SEO -> Titles & Metas
4- Click “HOME” tab
5- Replace the existing “template” with the site title text that you want to display
6- Click “Post Types” tab. Replace all instances of %%sitename%% with the name of your site (like “big.info”)
7- Click “Taxonomies” tab. Replace all instances of %%sitename%% with the name of your site (like “big.info”)
8- Click “Other” tab. Replace all instances of %%sitename%% with the name of your site (like “big.info”)
9- Click “Save Changes”
Now you should be good to go. Your site title on your home page should be fixed. Titles of the post pages, category pages etc. should all be fine.
Doing these will result in loosing your site name that appears in the login/registration pages as “Back to <site name>” link. To fix this:
1- Open wp-login.php
2- Ctrl+f “back to”
3- Remove “, get_bloginfo( ‘title’, ‘display’ )”
4- Replace “%s” with your site name
Hope this helps.