Error 'Cannot redeclare ctools_menu_add_tab()' after migrating website After our hosting provider has migrated our website to a new server this fatal error occurs when accessing the site:


  Fatal error: Cannot redeclare ctools_menu_add_tab() (previously
  declared in
  /www/htdocs/mysite/drupal/sites/all/modules/ctools/includes/menu.inc:42)
  in
  /www/htdocs/mysite/drupal/sites/all/modules/ckeditor/ctools/includes/menu.inc
  on line 49


Now the mother of all questions: How can I fix this? :(

We're using Drupal 6 and – although I haven't checked it yet – all files and databases should have been copied correctly by our hosting provider.
You have ctools installed twice, in:


sites/all/modules/ctools
sites/all/modules/ckeditor/ctools


Obviously the second path must have been mistake. If you can acces your page, disable ctools and then remove second instance. If you can't, try to do it using drush. If that fails, too, consider re-migration, this time properly. If all else fails, you may try to simply remove second instance and call update.php to perform some cleanup.