Download thunderbird version 60. Newer versions has difficult instructions to import mbox file and these instructions dont apply to them.
https://download.mozilla.org/?product=thunderbird-60.9.1-SSL&os=ein64&lang=en-US
Open Mbox file in Thunderbird
Download thunderbird version 60. Newer versions has difficult instructions to import mbox file and these instructions dont apply to them.
https://download.mozilla.org/?product=thunderbird-60.9.1-SSL&os=ein64&lang=en-US