Ensure you have debugging turned on to developer. Install a language pack with an underscore in its lang code (I used en_us) Make sure it is enabled. I just did it using the drop down at the top of the site (next to the site name) Navigate to "Site administration" > "Development" > "Template library" Click "core/form_autocomplete_selection" Ensure the "Example" and "Documentation" area display correctly and no errors are displayed Try some more templates if you want Go to "Site administration > Appearance > Manage tags" Create and delete tags, change tag type, set remove flag, rename tags - make sure all functionality works there Edit your user profile, make sure you can set and change your interests