With ImportExportTools NG, right-click a selection of messages, then Save selected messages (see picture).

https://addons.thunderbird.net/en-US/thunderbird/addon/importexporttools-ng/

OmG.... I finally was able to figure out a fix! 1) GET PrintingTools NG extension 2) In the MailNews Display dropdown check 'Select Messages' this causes a little check box to show up next to each message. 3) Check the boxes of the messages you want to print. 4) While all of the messages are selected, hit the "PrintingTools NG icon" that then pops your native 'print panel' up. 5) In the print panel configure the way you want these messages to be presented 6) Go to the "PDF" dropdown and choose Open PDF in Preview (or your preferred pdf viewer). "Leave the Print button alone! WALLLA Good luck

Thanks, but I had already tried this and it doesn't seem to work with my Mac. It basically only exports one email as a PDF then stops.

OmG.... I finally was able to figure out a fix! 2) In the MailNews Display dropdown check 'Select Messages' this causes a little check box to show up next to each message. 3) Check the boxes of the messages you want to print.

or just hold the CTRL key on the keyboard while you select them with your mouse.

Those check boxes were introduced for the visually impaired that needed a screen reader option to provide an aural feedback to selecting. One of the main reasons they are not visible by default is they are provided as an accessibility option and are not required for normal usage. The CTRL and SHIFT keys provide a faster, simpler and easier interface to achieve the same outcome without any screen clutter for those that do not need a screen reader.

Thanks, but I had already tried this and it doesn't seem to work with my Mac. It basically only exports one email as a PDF then stops.

That will be because you only have one email selected. See in the image where the menu starts with "save selected messages" The use of CTRL key to select multiple messages will have a impact on your results.

Alternatively use the addons menu entry on the tools menu to "export all messages in folder" as PDF instead of "selected messages" if you have them all in a single folder.

Thanks, yes I know about selecting multiple emails, but I'd already tried with the ImportExportTools NG add-on, and I get a javascript error message, "Because of a Thunderbird bug, the feature is not available on this platform."

Try the latest beta, 12.0.2, which is supposed to fix pdf output on OS X:

https://github.com/thundernest/import-export-tools-ng/issues/338

https://support.mozilla.org/en-US/kb/installing-addon-thunderbird

Wow, you rock! This worked - thanks!!!