iSync: SyncSession record validation failure

ISyncSession record validation failure: Value other pushed for enumeration property service on is not an allowed value. </p>

If you get above error while synchronising your OSX addressbook with Google Contacts, you might want to remove various IM types (Skype, Google Talk, etc) specified for contacts. OSX AddressBook can only accept "AIM", "Yahoo", "Jabber", "MSN" and "ICQ" as types.