I am trying to migrate to Thunderbird from Outlook 2010. I am using the TB import functions for Outlook on a machine with outlook installed. All of my mail messages come into TB correctly except those in my "Sent" folders (email I have sent to others). In >90% of these, the email address I sent From and the addresses I sent To are all replaced with text names. This makes it impossible to "reply all" for example as the entities that should be addresses are only names. A suggestion was previously made to turn off the Thunderbird option to Display address Book names instead of email addresses for contacts in your address book, but this option was already off. I am about to try deleting my address book in Outlook and then import again and see if this "breaks any links" that might be existing in Outlook. Does anyone have any ideas on how to make these email import correctly? Has anyone else noticed this behavior in the Sent mails folders when importing from Outlook?