It looks like the SOGo-Connector Add-On is not installed, which is required for the CategoryManager to work! The following errors have been found: CategoryManager [category_tools.js]: failed to include 'chrome://sogo-connector/content/addressbook/categories.js' (Error opening input stream (invalid filename?): chrome://sogo-connector/content/addressbook/categories.js) CategoryManager [category_tools.js]: failed to include 'chrome://sogo-connector/content/general/sync.addressbook.groupdav.js' (Error opening input stream (invalid filename?): chrome://sogo-connector/content/general/sync.addressbook.groupdav.js) Required function 'SynchronizeGroupdavAddressbook' is not defined. Required function 'isGroupdavDirectory' is not defined. Required object 'SCContactCategories' is not defined. If you DO have the SOGo-Connector installed, please report this issue to john.bieling@gmx.de.