Unable to import contact or emails to 'thunderbird. Have them backed up as .eml and .vcf files in separate folders. Have followed the instructions in your link https://support.mozilla.org/en-US/kb/switching-thunderbird#w_importing-windows-mail-contacts relating to "...install the MoreFunctionsForAddressBook add-on following these instructions....." The .xpi file has been downloaded but will not open or accept being moved to 'add-ons' Before abandoning 'thunderbird' I would appreciate some assistance. thanks in advance.