Opening Mails in Thunderbird (under Fedora 23)

[Andreas Aßmann]

Opening Mails in Thunderbird (under Fedora 23 and older versions)

Each time I receive mails in Thunderbird, I can open them without any 
problem, but ONLY as long as these mails remain INSIDE the Thunderbird-GUI.

But as soon as I store a mail OUTSIDE that graphical user interface, 
e.g. on a usb-stick or elsewhere on a hard disk, it is impossible to 
open again that same mail with Thunderbird. I then use Sylpheed because 
there's no other way.

Does anyone know what has to been done to get mails opened with 
Thunderbird OUTSIDE the GUI?

Thanks, greetings

Andrew