RE: ''outlook address book'' There is an ongoing issue regarding importing mail and address books from outlook using the import menu items mentioned. The bugzilla people are currently working on this. You can follow the progress from this link. Please note it is not a help forum and is used by bugzilla for communication. * https://bugzilla.mozilla.org/show_bug.cgi?id=1175055 The reason it is greyed out is because using it causes a crash at the moment, but it a temporary 'grey out' due to be enabled again in the near future. Methods on importing: If you export the outlook address book as .csv file, you can then import it into thunderbird. Before importing the .csv file, I would recommend you open the .csv file in something like Excel and check/modify the column headers so that they match the names used in Thunderbird. It is not essential to do this, but it does make mapping of Outlook column headers to Thunderbird column headers much easier. This link tells you the column headers names used in Thunderbird. * http://kb.mozillazine.org/Import_address_list_from_text_file To import: Address Book Tools > Import select 'Address books' and click on next select 'Text file' and click on next map the outlook fields/column headers to the Thunderbird column header fields. The only other way to import Outlook Mail and Address Books using the 'greyed out' options (enabled in earlier version): Download and install an older version of thunderbird. Try version 31 or 24. You can find these downloads here: * http://ftp.mozilla.org/pub/thunderbird/releases/24.0/ * http://ftp.mozilla.org/pub/thunderbird/releases/31.0/ Then select the one suitable for your OS. eg: Win32 for Windows OS then select the language of choice eg: en-GB = English (British) then download the thunderbird setup exe file. After importing you can then use the update Thunderbird to use the recent release which is version 38.5.1 Hope this info helps your situation.