Symptoms

The following appears in the atlassian-confluence.log:

WARN [atlassian.confluence.themes.DefaultThemeManager] extractTheme Unable to find configured theme module: com.atlassian.confluence.themes.classic:classic

WARN [atlassian.confluence.themes.DefaultThemeManager] extractTheme Unable to find configured theme module: com.artemis.commentstab:commentstab-theme

Depending on the add-on, you may also see "Unknown macro" errors displayed on pages:

Cause

These log messages occur after Confluence was configured to use a site-wide theme that was installed via an add-on. After the add-on is uninstalled, Confluence automatically reverts back to the default theme but the now non-existent theme is still referenced internally. This causes the 'missing theme module' log messages to appear. More information about this bug can be found in the bug report CONF-14838 - Getting issue details... STATUS .

Resolution

1. First, you want to bring back the add-on, so that the references mean something again. Re-install the add-on which provides the theme.
2. If you really did want to remove the theme, change the global theme and change the theme for any affected spaces, to a  theme other than the one that caused the error.
3. Once you've changed the theme in the global settings and all applicable spaces, you can then uninstall the add-on once again.

1. Find all spaces that are using the wrong theme:

   SELECT *
   FROM BANDANA B, SPACES S
   WHERE B.BANDANAKEY='atlassian.confluence.theme.settings'
   AND S.SPACEKEY=B.BANDANACONTEXT
   AND B.BANDANAVALUE LIKE ('%<theme_name>%')
   ORDER BY S.SPACENAME;

   Replace <theme_name> with the name that appears in the logs.
   
   

2. Update the BANDANA table directly in the database:

   UPDATE BANDANA
   SET BANDANAVALUE= '<map>
     <entry>
       <string>theme.key</string>
       <string></string>
     </entry>
   </map>'
   WHERE BANDANAKEY='atlassian.confluence.theme.settings'
   AND BANDANACONTEXT='<spacekey>';

    Replace <spacekey> with the space key returned in the first query.