Small update : I tried renaming the created msf file with the correct name, it doesn't work... also if you have an idea but need like commands and such, could you please precise where I type said command, since I'm not that tech savvy, thank you.

As no one appears interested, perhaps you could advise what a FLUX is. In my business flux is a chemical cleaning agent, flowing agent, or purifying agent especially in soldering or welding so you loose me in your first statement.

What MBOX file? where from? not all mbox files are created equal https://en.wikipedia.org/wiki/Mboxand https://www.loc.gov/preservation/digital/formats/fdd/fdd000383.shtml . Apple mail used to use the same format as Thunderbird, but no longer despite the file extension still being mbox

As no one appears interested, perhaps you could advise what a FLUX is. In my business flux is a chemical cleaning agent, flowing agent, or purifying agent especially in soldering or welding so you loose me in your first statement. What MBOX file? where from? not all mbox files are created equal https://en.wikipedia.org/wiki/Mboxand https://www.loc.gov/preservation/digital/formats/fdd/fdd000383.shtml . Apple mail used to use the same format as Thunderbird, but no longer despite the file extension still being mbox

I got my app in french, but yeah, flux is translated to feed... kinda dumb on that point... also all the e-mails seems to have been written on the same device, and since out of 51, only like 7 or 8 work, I assume they aren't written in an apple device... and they're old used mails from someone else... I have no idea if that helped or anything... hope it does...

Open the files in a text editor (notepad++ is the usual recommendation as windows notepad just chokes on huge files). You can use any text editor, but Microsoft word is not a text editor.

The layout of the file is text. Scroll down to the part that joins two EML email files. so basically the text of one email will end, and the next will start often with a From line followed by email headers. What does the separator look like? That is how to determine which type of Mbox file you have, as the main difference in in that new mail space.

Thunderbird uses a line like From - Mon Jan 15 21:53:52 2024

Open the files in a text editor (notepad++ is the usual recommendation as windows notepad just chokes on huge files). You can use any text editor, but Microsoft word is not a text editor. The layout of the file is text. Scroll down to the part that joins two EML email files. so basically the text of one email will end, and the next will start often with a From line followed by email headers. What does the separator look like? That is how to determine which type of Mbox file you have, as the main difference in in that new mail space. Thunderbird uses a line like From - Mon Jan 15 21:53:52 2024

The separator is the same as you said : From - Thu Dec 01 10:42:14 * 2022

however right where the star is, there is a series of numbers, like +0000 for example... I don't think it changes much, and I have no Idea what to do in that case... any Idea ?

For some reasons, I redownloaded the files for the third or fourth time, and it worked... huh... well I guess the post isn't useful then...

well it is working. That is really all that matters.