Are there any email software like ancient eudora with simple file system

Question

Ancient eudora is simple. You can store all your mail and all your settings and all your filters in the same folder. And that's it.

Nothing in registry. Nothing in the hidden folder of user's application data. Just a custom folder you can specify.

Answer 1

The original Eudora (as opposed to its new Thunderbird based version) used the mbox format, or a varient of it. Off the top of my head claws does something similar and can use the classic mbox format with a plugin

I'd also look at mail clients that support maildir like opera