[https://support.mozilla.org/en-US/kb/switching-thunderbird#w_switching-from-windows-mail-or-windows-live-mail-to-thunderbird This article] is somewhat outdated, but still relevant for exporting data from WLM. For importing eml files to TB, the relevant add-on is [https://addons.thunderbird.net/en-US/thunderbird/addon/importexporttools-ng/ ImportExportTools NG], or you can simply drag a set of eml files from Explorer and drop them onto a subfolder of Local Folders in TB. For contacts, merge the vCards into a single .vcf file and import it to TB (Tools/Import...): https://support.mozilla.org/en-US/questions/1280605#answer-1292936